16 May 2015

Dreaming a Different Apollo, Part One

Skylab 1 Orbital Workshop atop a Saturn V rocket (foreground) and Skylab 2 Saturn IB rocket (background). Image credit: NASA
Apollo didn't die; it was killed. The Apollo Program might have continued for many years, evolving constantly to achieve new goals at relatively low cost. Instead, programs designed to give Apollo a future beyond the first lunar landing began to feel the brunt of cuts even before Neil Armstrong set foot on the moon. By the time Apollo drew to its premature conclusion - the last mission to use Apollo hardware was the joint U.S.-Soviet Apollo-Soyuz Test Project (ASTP) of July 1975 - NASA was busy building a wholly new space program based on the Space Shuttle. Throwing out the Apollo investment and starting over with Shuttle was incredibly wasteful both in terms of learned capabilities and money.

Apollo as we knew it included over its seven-year series of flights a total of seven major hardware elements. They were: the Saturn V rocket, available in three-stage and two-stage varieties; the two-stage Saturn IB rocket; the Apollo Command and Service Module (CSM) spacecraft; the Apollo Lunar Module (LM) moon lander; the jeep-like Lunar Roving Vehicle (LRV); the Skylab Orbital Workshop, a temporary space station; and the ASTP Docking Module (DM).

Apollo missions 1, 2, and 3 either did not fly (in the case of Apollo 1, which killed astronauts Gus Grissom, Edward White, and Roger Chaffee on 27 January 1967) or were cancelled (in the case of Apollo 2 and Apollo 3). Flown missions began with Apollo 4, the first unmanned test of the Saturn V rocket (9 November 1967). Apollo 5 was a Saturn IB-launched unmanned LM test. Apollo 6 was a second unmanned Saturn V rocket test.

All subsequent Apollo and Apollo follow-on missions save one (Skylab 1) were launched bearing three-man crews. Apollo 7 (11-22 October 1968), the first piloted Apollo, was a Saturn IB-launched CSM-only mission in low-Earth orbit. It accomplished the mission originally planned for Apollo 1. Apollo 8 (21-27 December 1968) was a Saturn V-launched lunar-orbital CSM-only mission motivated by rumors of a Soviet piloted circumlunar flight, Apollo 9 was a Saturn V-launched, Earth-orbital CSM/LM test, and Apollo 10 was a lunar-orbital dress rehearsal for Apollo 11 (16-24 July 1969), which carried out the first piloted lunar landing.

NASA gave alphanumeric designations to the Apollo missions; Apollo 8 was, for example, designated C-prime. Apollo 11 was the first and only G-class mission. The Apollo 11 moonwalk lasted a little over two hours and the crew remained on the moon for only 22 hours. Though momentous (and the signal to most people that Apollo could end), Apollo 11 was really a full-up engineering test of the Apollo lunar mission system from Earth launch to Earth splashdown and post-mission quarantine. It paved the way for the H-class missions: Apollo 12 (H-1) which, after a pinpoint landing near the unmanned Surveyor III lander, included a 32-hour surface stay and two moonwalks; Apollo 13 (H-2), the "successful failure" (as NASA called it) which through adversity hinted at Apollo's untapped potential; and Apollo 14 (H-3), which included the longest lunar surface traverse on foot of the Apollo Program.

NASA originally planned for Apollo 15 to be H-4, but upgraded it to J-1 after NASA Administrator Thomas Paine, in an ill-advised attempt at horse-trading with the Nixon White House, cancelled one H mission and one J mission. J missions included LMs with longer landing hover times, lunar surface stays of about three days, improved space suits supporting up to four moonwalks, and an electric-powered LRV. Individual moonwalk duration was stretched to almost eight hours, in part because of suit improvements, but also because riding the LRV reduced astronaut metabolic rates; seated, they used less oxygen and cooling water than when on foot.

Apollo 17 Lunar Module Challenger at Taurus-Littrow, December 1972. Image credit: NASA
Apollo 16 was called J-2 and Apollo 17 in December 1972 was J-3. The last piloted moon mission of the 20th century, Apollo 17 was the final flight of the LM, the LRV, and the three-stage Saturn V.

Six months after it abandoned the moon, NASA launched Skylab 1, the first and only Skylab Orbital Workshop, unmanned atop the first and only two-stage Saturn V to fly. Three Saturn IB rockets each launched a CSM bearing three men to Skylab 1 for stays of up to 84 days. They lifted off from a makeshift raised platform ("the milkstool") on Saturn V Pad 39B. The last mission, Skylab 4, returned to Earth in February 1974.

Eighteen months after Skylab, the last Saturn IB to fly launched the last CSM to fly into low-Earth orbit for a meet-up with a Soviet Soyuz spacecraft. The last CSM was named only "Apollo." The first and only DM, an airlock that enabled crews to move safely between the incompatible atmospheres of the Apollo and Soyuz spacecraft, rode inside the tapered shroud that linked the bottom of the CSM to the top of the Saturn IB's S-IVB second stage.

Upon reaching Earth orbit, the ASTP Apollo spacecraft turned end for end, docked with the DM, detached it from the S-IVB, and began maneuvers that led to the first international docking in space. On 24 July 1975, six years to the day after Apollo 11 returned from the moon, the ASTP Apollo CSM parachuted to a splashdown in the Pacific.

Though Apollo hardware remained, none of it reached space. A second Skylab workshop was placed on display in the National Air and Space Museum in Washington, DC. Two Saturn Vs, one of which might have launched the second Skylab, and an assortment of Saturn IB rockets, CSMs, and LMs in various states of completion were parceled out to NASA centers and museums for display or were scrapped.

President Lyndon Baines Johnson, a NASA supporter (in 1958, as Senate Majority Leader, he had been instrumental in its creation), predicted Apollo's premature end. In 1967, Congress slashed to just $122 million the $450 million he requested to start the Apollo Applications Program (AAP). AAP - which would rapidly shrink to become the Skylab Program - had been intended to exploit Apollo hardware and operational experience to accomplish new lunar and Earth-orbital missions. As news of the deep cuts in his AAP request reached the White House, Johnson mused that, "the way the American people are, now that they have all this capability, instead of taking advantage of it, they'll probably just piss it all away."

What if Johnson had got it wrong? What if, somehow, Americans cared more about space exploration and so sought to wring from their $24-billion Apollo investment everything they could?

The Soviet Union for many years numbered its Soyuz missions consecutively regardless of changes in spacecraft purpose and design. If Apollo had been allowed to survive and thrive, perhaps the United States would have adopted a similar numbering policy, ultimately yielding impressively high alphanumeric mission designation numbers. What follows is an unabashed exercise in alternate history speculation (and, above all, shameless wishful thinking). It is based on actual NASA and contractor plans and is written as though the events it recounts actually occurred.

A word of caution: in order to simplify an already complex timeline, I have ignored the possibility of accidents. Spaceflight is risky, yet in this alternate history all missions occur exactly as planned. The likelihood that every mission described below would come off as planned, with no mishaps or outright disasters, would in fact be very small.


Because no one sought to kill Apollo, NASA boss Paine felt no urge to trade away two Apollo missions in the vain hope that Nixon would support his plans for a large Earth-orbital space station. This meant that Apollo 15 remained H-4. The first J mission (J-1) was Apollo 16 and Apollo 17 was J-2.

Apollo Earth-orbital space station flights began in late 1971. Apollo 18 was the unmanned launch of the first two-stage Saturn V bearing a temporary Earth-orbiting space station. In keeping with NASA’s old penchant for program names from Greek and Roman mythology, the station was dubbed Olympus 1. The Olympus name had a heritage in the world of space station planning going back to the early 1960s.

The Apollo-derived Olympus station resembled the Skylab Orbital Workshop of our timeline, but lacked its side-mounted Apollo Telescope Mount and "windmill" solar arrays. It also included more internal decks.

Within days, Apollo 19, the first K-class Earth-orbital CSM, lifted off on a Saturn IB from Launch Complex 34 bound for Olympus 1 with three astronauts on board. K-class CSMs included batteries in place of fuel cells, an electricity umbilical for linking to the Olympus station power system, a retractable main engine bell to make more room in the S-IVB shroud, extra storage compartments in the Command Module (CM) capsule, an option to install up to two extra crew couches, a pair of small steerable dish antennas in place of lunar Apollo's large four-dish system, and smaller main-engine propellant tanks. It also included modifications that enabled it to remain semi-dormant attached to an Olympus station for up to six months (for example, heaters to prevent fluids from freezing in its tanks and propellant lines).

Apollo 19 remained docked to Olympus 1's axial ("front") docking port while its crew worked on board the station for 28 days – twice as long as any U.S. space mission before it. They returned to Earth on Christmas Eve 1971. The Apollo 20 (K-2) crew, launched on 23 January 1972, subsequently demolished Apollo 19's new record by living on board Olympus 1 for 56 days.

Apollo 21 (I-1), a Saturn V-launched mission to lunar polar orbit, marked the start of a new phase of Apollo lunar exploration. Two astronauts orbited the moon for 28 days in a CSM with an attached Lunar Observation Module (LOM) in place of an LM. From mid-March to mid-April 1972, the astronauts charted the moon's surface in great detail to enable scientists and engineers to select future Apollo landing sites and traverse routes.

Apollo 22 (K-3), launched in June 1972, delivered a three-man crew to Olympus 1 for a 112-day stay, doubling Apollo 20's stay-time. Ninety days into their mission, the two-man Apollo 23 (K-4) CSM docked at Olympus 1's single radial ("side") docking port for 10 days. One of the Apollo 23 astronauts was a medical doctor; he conducted health evaluations of the Apollo 22 astronauts. If any member of the Apollo 22 crew had been found to be unhealthy, then all would have returned to Earth in either their own CSM or with the Apollo 23 crew in its CSM, which included three spare couches (the empty Science Pilot couch and two couches located against the Apollo 23 CM’s aft bulkhead).

As it turned out, the Apollo 22 astronauts were in good shape and high spirits, so NASA authorized continuation of their mission to its full planned duration. Before returning to Earth, the Apollo 22 crew used their CSM's main engine to boost Olympus 1 to a higher orbit, postponing its reentry by up to 10 years.

NASA referred to the Apollo 22 astronauts as the third Olympus 1 resident crew and the Apollo 23 astronauts as the first Olympus 1 visitor crew. The full alphanumeric designations for Apollos 22 and 23 were O-1/K-3/R-3 and O-1/K-4/V-1, respectively. Most people did not pay attention to those designations, however, being satisfied to call the missions by their Apollo numbers.

NASA ordered 15 Saturn V rockets for the Apollo Program. In 1968, NASA Deputy Administrator for Manned Space Flight George Mueller asked NASA Administrator James Webb for permission to order more Saturn V rockets for AAP. With budgets for post-Apollo space programs already under fierce attack, Webb rejected Mueller’s request.

In our alternate timeline, Webb's answer was different. Apollo 24 (J-3) (October 1972) used the last Saturn V of the original Apollo buy. This fact aroused only passing interest, however, since in our alternate timeline no one ever seriously considered halting the Saturn V assembly lines. Apollo 25 (J-4) launched atop the first new-buy Saturn V, the 16th Saturn V to be built.

Two months after the Apollo 24 LM ascent stage lifted off from the lunar surface, the Apollo 25 LM landed about a kilometer away from the derelict Apollo 24 LM descent stage. The Apollo LM descent engine kicked up potentially damaging dust during landing, so the Apollo 25 astronauts inspected Apollo 24's descent stage, LRV, and ALSEP experiments to determine whether a one-kilometer landing separation distance was adequate.

The Apollo 25 crew carried out other technology experiments. They deployed an experimental solar array designed to withstand the cold of the two-week lunar night and a small battery-driven remote-controlled rover. Controllers on Earth drove the small rover several hundred meters in preparation for longer remote-controlled traverses to come.


Apollo 26 (O-2) (January 1973) was the Saturn V launch of the Olympus 2 space station. It lifted off from Pad 39C, a new Complex 39 launch pad north of the existing 39A and 39B pads at Kennedy Space Center (KSC), Florida. 39C was designed for both Saturn V and Saturn IB launches, putting NASA on track to retiring the Complex 34 Saturn IB pad located south of Kennedy Space Center, within the boundaries of Cape Canaveral Air Force Station.

Soon after Olympus 2 reached orbit, the last Saturn IB to use Complex 34 launched Apollo 27 (O-2/K-5/R-1). Its epic mission: to stretch the world spaceflight endurance record to 224 days. Over the course of the Apollo 27 mission, NASA launched four unmanned Saturn IB rockets with Centaur upper stages. Though not given Apollo numbers, the flights are often referred to unofficially as Apollo GEO A, Apollo GEO B, Apollo GEO C, and Apollo GEO D. Two lifted off from Pad 39C and two from newly upgraded Pad 39A.

Each boosted into geostationary orbit one Radio/TV Relay Satellite (RTRS); three operational satellites and a spare. Olympus 2 thus became the first space station capable of uninterrupted voice, data, and TV contact with Mission Control at the Johnson Space Center in Houston, Texas, and Payload Control at the Marshall Space Flight Center in Huntsville, Alabama.

The Saturn IB-launched Apollo 28 CSM lifted off from Pad 39C 45 days into the Apollo 27 crew's stint on board Olympus 2. The six-day, three-person mission, designated O-2/K-6/V-1, included the first female U.S. astronaut. Apollo 29 (O-2/K-7/V-2), another six-day, three-person mission, reached Olympus 2 110 days into the Apollo 27 mission. It included the first non-American to fly on a U.S. spacecraft.

Apollo 30 (O-2/K-8/V-3), a 10-day, two-person mission nearly identical to Apollo 23, reached Olympus 2 190 days into the Apollo 27 mission. The Apollo 27 astronauts proved to be in good health, so NASA authorized them to continue their mission to its full planned duration. The Apollo 30 crew returned to Earth in Apollo 27's CSM, leaving behind their fresh CSM for the long-duration astronauts. The Apollo 27 crew used the Apollo 30 CSM's main engine to boost Olympus 2 to a higher orbit with an estimated lifetime of more than a decade.

Just before the Apollo 27 crew ended their record-setting stay in space in July 1973 - a record that would hold for more than a decade - the unmanned Apollo 31 Saturn V launched a pair of modified RTRS satellites (one operational and one spare) into a loose orbit around the quasi-stable Earth-moon L2 point, 33,000 miles beyond the moon. When NASA launched Apollo 34 (J-5) to the moon’s Farside hemisphere, out of sight of Earth, the satellites provided continuous radio, data, and TV communication with both the CSM while it orbited over the Farside hemisphere and the LM parked on the Farside surface.

The Apollo 32 (O-3) Saturn V launched Olympus 3 - intended to be the first "long-life" space station - from Pad 39A (December 1973). Olympus 3 included three equally spaced radial docking ports, expanded solar arrays, an uprated life support system, a "greenhouse" plant growth chamber, improved internal lighting, an observation cupola, and guest living quarters.


The next month, the three-man Apollo 33 (O-3/K-9/R-1) crew lifted off from Pad 39C to begin a 180-stay on board. Starting with Apollo 33, 180 days became the standard duration for Olympus station missions. The Apollo 27 crew had remained on board Olympus 2 for 224 days so that NASA could have in place a "cushion" of biomedical knowledge in the event that a 180-day mission had to be extended; for example, if a resident crew's CSM proved faulty when time came to return to Earth and a rescue mission had to be mounted.

Apollo 34 (J-5) (February 1974) was, as indicated above, the first piloted mission to the moon's hidden Farside. The last of the J-class lunar landing missions, its crew included the first woman on the moon.

Olympus 3 could support visiting crews for longer periods, permitting Apollo 35 (O-3/K-10/V-1) to be the first three-person, 10-day visitor mission. It delivered the first Cargo Carrier (CC-1) to Olympus 3 60 days into the Apollo 33 mission. Drum-shaped CC-1 rode to orbit inside the segmented shroud between the top of the Saturn IB's S-IVB second stage and the bottom of the Apollo 35 CSM's engine bell.

After S-IVB shutdown, the Apollo 35 crew separated their CSM from the shroud, which peeled back in four parts and separated from the stage. They then turned their CSM end-for-end to dock with CC-1's "outboard" docking port and detached the carrier from the S-IVB.

Image credit: NASA/David S. F. Portree
The Apollo 35 CSM docked with one of Olympus 3's three radial ports using CC-1’s "inboard" docking port. Its crew then entered the station through CC-1's meter-wide central tunnel. When their visit with the Apollo 33 crew drew to an end, they undocked their CSM from CC-1, leaving the carrier attached to Olympus 3 so that it could serve as a "pantry" or "walk-in closet."

Apollo 36 (O-3/K-11/V-2) was another 10-day, three-person visitor mission to Olympus 3. Its crew included an African-American mission Commander who had flown first as Command Module Pilot on Apollo 24. The Apollo 36 CSM docked with CC-1's outboard port 120 days into Apollo 33. When time came to return to Earth, they undocked CC-1's inboard port from Olympus 3. Following their deorbit burn, they undocked their CSM from CC-1's outboard port and performed a small separation maneuver. CC-1, packed with trash, burned up in Earth’s atmosphere, and the Apollo 36 CM capsule splashed down in the Pacific.

The Apollo 33 resident crew undocked from Olympus 3 and returned to Earth, and two weeks later the Apollo 37 (O-3/K-12/R-2) CSM arrived with Olympus 3's second resident crew and, on its nose, a hefty telescope module. The crew gingerly docked the telescope module to the radial port on the side of Olympus 3 opposite the radial port used for Cargo Carriers, then undocked their CSM from the telescope module's outboard port and redocked with Olympus 3's axial port. Olympus 3 thus became the world's first multi-modular space station.

Attention then shifted back to the lunar track of the on-going Apollo Program. Apollo 38 (L-1A) (August 1974) saw an unmanned uprated Saturn V-B rocket launch directly to the lunar surface an LM-derived Lunar Cargo Carrier (LCC-1) bearing a nuclear-powered Dual-Mode Lunar Rover (DMLR). The piloted Apollo 40 (L-1B) mission saw the first Augmented CSM (ACSM) and the first Augmented Lunar Module (ALM) launched to lunar orbit on a Saturn V-B. The Apollo 40 ACSM remained in continuous contact with Earth over the moon's Farside hemisphere through the RTRS satellites at Earth-moon L2.

The ALM descended to a landing within about a kilometer of LCC-1. The astronauts deployed the DMLR and drove it on five traverses during their one-week stay on the moon. They then reconfigured it for Earth-guided operation. After the DMLR retreated to a safe distance under Earth control, the Apollo 40 ALM ascent stage ignited to return the crew to the orbiting ACSM and, subsequently, to Earth.

In October 1974, a month after the Apollo 40 astronauts left the moon, DMLR began a 500-kilometer overland trek to the next planned Apollo landing site. As it moved slowly over the rugged surface, it imaged its surroundings, took magnetometer readings, and occasionally stopped to collect an intriguing rock or scoop of dirt. A pair of spotlights permitted limited lunar night-time driving. Assuming that the DMLR reaches its goal, the next ALM crew, set to land next to a pre-landed LCC in July 1976, will retrieve its samples for return to Earth, reconfigure it for astronaut driving, use it to explore their landing site, and then reconfigure it again for Earth-guided operation.

Image credit: NASA
Sandwiched between Apollo 38 and Apollo 40 was Saturn IB-launched Apollo 39 (O-3/K-13/V3), a routine 10-day visitor mission to Olympus 3 bearing Cargo Carrier-2. Apollo 39 docked CC-2's inboard port with one of Olympus 3's two unoccupied radial docking ports.


The Apollo 41 (O-3/K-14/R-3) CSM docked with the third Olympus 3 radial port bearing the station's third resident crew in early January 1975. The start of their mission overlapped the end of the Apollo 37 resident crew's 180-day stay in space. The handover in marked the start of Olympus 3's continuous occupation, which lasted until the station was safely deorbited in July 1979.

Apollo 42 (O-3/K-15/V-4), another 10-day visitor mission to Olympus 3, docked at the CC-2 outboard port in March 1975 and, when they returned to Earth, deorbited CC-2 over the Pacific Ocean. Apollo 43 (O-3/K-16/V-5) in May 1975, was the second 10-day mission to visit the Apollo 41 resident crew. They delivered CC-3.

Apollo 44 (0-3/K-17/R-4) docked with Olympus 3 on 19 December 1975. On their way to Olympus 3, they performed a rendezvous with Olympus 1 to assess its condition. Apollo 41's return to Earth on 31 December 1975 rounded out NASA's 1975 piloted spaceflight schedule.

On our alternate timeline, NASA's Apollo-based piloted space program is hitting its stride. Earth-orbital operations are becoming routine; lunar-surface operations are continuing to evolve and advance.

On our own timeline, Apollo has drawn to its ill-considered close. Apollo would attract general public notice twice before the first Space Shuttle flight in April 1981: in September 1977, when funding cuts compelled NASA to shut off the science instruments the six Apollo lunar landing crews left behind on the moon; and in July 1979, when Skylab reentered Earth's atmosphere less than a week ahead of Apollo 11's 10th anniversary, pelting Australia with debris.

15 May 2015

Fun with Killer Asteroids

I wrote the post below in January of this year for my WIRED Science Blog Beyond Apollo during a senseless media frenzy centered on a not-very-threatening near-Earth asteroid called 2004 BL86. Over the past several days, some media outlets have sought to do the same with asteroid 1999 FN53, a roughly 700-meter-wide space rock that passed about 10 million kilometers from Earth yesterday (Thursday, 14 May 2015). Probably it's a good time to repost.

Itokawa, sampled in 2005 by Japan's Hayabusa spacecraft, is in the same size class as 2004 BL86. Image credit: JAXA
To date, human beings have spotted more than 500,000 asteroids. These range in scale from 950-kilometer Ceres, the first asteroid discovered, way back on the first day of the 19th century, to unnamed boulders. Little asteroids (say, the size of a bus or a house) far outnumber the big ones.

Ceres resides in the Main Belt between Mars and Jupiter, as do the vast majority of asteroids. Only about 15,000 follow paths around the Sun that bring them near Earth's orbit. That's a crucial detail, by the way; they approach Earth's orbit regularly, but not necessarily Earth itself. As with the Main Belt asteroids, little near-Earth asteroids greatly outnumber large ones.

The largest of the near-Earth asteroids is 1036 Ganymed, which measures about 33 kilometers across. It has a stony composition much like that of the second-largest near-Earth asteroid, banana-shaped 433 Eros, which measures 34 kilometers by 11 kilometers. Eros never draws nearer than about 27 million kilometers from Earth, or about 70 times the Earth-moon distance; Ganymed never passes closer than about 56 million kilometers. Both of these small bodies were discovered before 1925.

Eros is unique because a derelict American spacecraft called NEAR Shoemaker rests on its surface; though designed as an orbiter, it landed on Eros on 12 February 2001, at the end of its mission, and continued to transmit for about two weeks. Eros has peculiar "ponds" made of fine dust; it is thought that NEAR Shoemaker happened to fall on one, softening the force of its impact.

A day or so ago, a 325-meter asteroid designated 2004 BL86 passed Earth. To get a sense of perspective, 325 meters, or roughly as wide as the Tour Eiffel is tall, is kind of big for a near-Earth asteroid. As asteroid flybys go, it was a close shave; 2004 BL86 passed about 1.2 million kilometers from Earth. That distance is a bit more than three times the distance between the Earth and the moon.

Any time an asteroid is due to pass Earth – even if it will pass more than a million kilometers away – the popular-audience space media kicks into inaccuracy overdrive. Adjectives I heard used to describe 2004 BL86 included "giant," "huge," "mountain-sized," and "dangerous." Phrases used to describe its minimum-approach distance included "so close you’ll be able to see it," "very close," and "a close encounter." None of this language was accurate. One media source even called it the biggest asteroid to approach Earth in 200 years; in fact, this was the closest approach of this asteroid for 200 years.

The news media are not the only ones that commit such errors. Space educators who should know better also play up the "threat" from "killer" asteroids when a body like 2004 BL86 passes the Earth-moon system. They place objects like 2004 BL86 in the same category as the "dinokiller" that struck Earth 65 million years ago.

Doing that falls short in the reality department in at least a couple of ways: for one thing, the impactor that ended the Cretaceous was an extraordinary object for a near-Earth asteroid, of roughly the same magnitude as Eros or Ganymed, and such bodies hit Earth on time scales of tens of millions of years; for another thing, an object nearly as large as the dinokiller impactor struck Earth 35 million years ago where now Chesapeake Bay is located, and it caused no mass extinction. It wasn't even known until the mid-1990s, and then only because one of its byproducts is brackish well water in eastern Virginia. So, even for truly big impactors, mass extinction is not inevitable.

Because of the poor quality of information they receive, many people with only a casual interest in space have developed the mistaken notion that asteroids are frightening things. In fact, they are data-packed fossils of the formation of our Solar System. The appropriate emotion to feel when one of these objects passes by Earth is not fear; it is fascination.

As proof of the sheer nifty-ness of asteroids, I offer this: as 2004 BL86 passed Earth on 26-27 January, observers aimed telescopes at it. By carefully gauging changes in the amount of sunlight reflected off the asteroid, they found that it might not travel through space alone. Earth-based radars then confirmed that a moon about 70 meters across circles 2004 BL86 at a distance of about 500 meters. How cool is that?

I think by now you realize that I do not endorse exploiting asteroids to scare people, no matter how slow a news day it might be. Just for grins, though, how about we imagine that 2004 BL86 tried to live up to the fearsome adjectives used to describe it and had actually struck the Earth?

The nice people at University College London (UCL) and Purdue University have conspired to create a handy online impact modeling tool called "Impact: Earth!" I prefer the less graphics-intensive 2010 version – to be found here – which is called, more prosaically, "Earth Impact Effects Program." The latter operates faster and allows me to use my imagination more.

The minds behind this modeling tool are careful to warn us that it might not be perfect. In fact, they warn that, if one enters "peculiar impact parameters" they refuse to be responsible for what happens. The model does, however, provide results in line with those arrived at in scientific studies of impact effects, and the explanatory document that accompanies it is convincing.

We know from spectral analysis that 2004 BL86 is another stony asteroid like Eros and Ganymed; they are quite common. To be more precise, it is a V-type asteroid, meaning that it might well be a chip knocked off Vesta, the third-largest and second-most-massive asteroid in the Main Belt. We know that, given the shape and tilt of its orbit about the Sun, 2004 BL86 might be a bit more likely to intersect Earth near the equator than near the poles. Now we know that it has a moon, which should be taken into account when modeling impact effects.

So, first we choose an impact site. I spin my 16-inch Earth globe – around and around it goes, and where it stops, nobody knows – and halt it with my finger. I look at the place that I have picked: it is in the Pacific just east of the Japanese island of Honshu. I do not like that choice; after all, the poor folks there are still picking up the pieces after the giant earthquake-tsunami-reactor meltdown disaster of 11 March 2011, and a nearby impact would be piling on.

I spin the globe again; this time my finger falls on the Atlantic Ocean about 300 kilometers east of The Bahamas. People there have to deal with killer hurricanes, but if this experiment is to have meaning I have to be dispassionate. So, it's east of The Bahamas for our impact site (sorry, Bahamians and their neighbors).

The modeling software allows me to select my distance from the impact point. Of course, I am tempted to put myself far enough away that I could conceivably be in a cafe in Paris, but I will instead suck it up and put myself in harm's way. I'll imagine that I am in Puerto Rico, about 300 kilometers south of the impact point. After all, I've long wanted to visit Puerto Rico to see Arecibo Observatory and old San Juan.

Next, I will enter the impactor's size, starting with 2004 BL86 by itself (I will add the newly found moon later). Now I need to decide on its density. I select "dense rock" with a mass of 3000 kilograms per cubic meter. The average asteroid impact velocity is 17 kilometers per second, but I will ramp it up a bit to 23 kilometers per second because of the shape of 2004 BL86's orbit about the Sun. The most probable impact angle is 45°, so I’ll go with that. I want to avoid "peculiar impact parameters," after all.

Almost done. The last step is to define the target density. Three hundred kilometers east of The Bahamas is deep ocean. In fact, the deepest part of the Atlantic, the Puerto Rico Trench, is close by. I enter a target density for "water" of 1000 kilograms per cubic meter and a compromise depth of 3000 meters.

OK. All set. Here comes our asteroid. I click on the "calculate effects" button. According to the model, an impact on the scale of a 2004 BL86 impact occurs – can this be right? – about every 84,000 years. That seems pretty often, but it is 10 times longer than recorded human history.

2004 BL86 begins to disintegrate 59 kilometers above the ocean. It shatters into many small pieces by the time it hits the water. The pieces splash down in an ellipse measuring about 0.9 kilometers long by 0.6 kilometers wide. This produces a "crater" – a splash, really – about 7.9 kilometers wide. Fragments reach the sea floor, forming a submerged crater field. The largest crater in the field measures 194 meters across by 69 meters deep.

The impact fireball is below the northern horizon as viewed from Puerto Rico, so I feel no wave of heat from the impact. If the impact took place at night, I would see a brilliant flash on the horizon. The seismic effects at the impact site resemble a magnitude 3.6 earthquake. Three hundred kilometers away in Puerto Rico, I feel nothing.

For people used to hurricanes, the atmospheric effects of the hypothetical 2004 BL86 impact are a walk in the park. The roar of the impact is about as noisy as loud traffic. Air blown outward from the impact site reaches Puerto Rico traveling at a speed of 7.61 meters per second, or about 17 miles per hour.

The tsunami the impact generates reaches Puerto Rico's north coast 35 minutes after the impact. The wave is 14.4 meters high or less. Some coastal towns are inundated.

It's important to point out that we knew of the 2004 BL68 flyby well in advance. We can thus assume that we would know of a 2004 BL86 impact well in advance. It would not have been too difficult to calculate where it would hit. Because of this, it is reasonable to assume that the coastal towns could have been evacuated before the impact occurred. We can also assume that ships and aircraft would be kept out of the impact area in the hours before 2004 BL86 struck; these steps, not much different from those taken ahead of a hurricane or during a volcanic eruption, would dramatically reduce loss of life and damage to property.

What about 2004 BL86's 70-meter-diameter moon? I leave all the impact model parameters the same except the impactor diameter and click the button. The moon barely reaches the ocean surface, creating no splash and barely any wind. Its effects are lost among those of 2004 BL86. According to the UCL/Purdue model, lone impactors the size of 2004 BL86’s moon hit Earth every 2200 years; given that our recorded history is not pocked with accounts of such impacts, it would seem that when objects that size strike Earth, they are not much noticed.

These results are suggestive, not definitive. I will repeat that the modeling software is by its own designers' admission not perfect. Though I would defend my inputs as plausible, GI/GO applies. The point is, however, that it seems that a body the size of 2004 BL86 does not have much effect on the Earth when it strikes. No mass extinction occurs, the climate does not shift to some new harsh state, and the effects on human lives even close to the impact site are similar to those that people have long endured because of volcanoes, hurricanes, tornadoes, earthquakes, and warfare.

Do I argue here that we should treat near-Earth asteroids as a non-threat? Of course not. We should find all of them. We have the technology to do that (and by some estimates, we're almost done). We should also test techniques for deflecting them away from Earth. As we do these things, we can study them to learn more about our Solar System.

Perhaps along the way we can teach ourselves how to make mining them profitable. As far back as the 1960s, some people – notably Dandridge Cole – suggested that we convert asteroids into habitats or interplanetary transports. Isaac Asimov once called them "stepping stones to the stars." That is, he suggested that asteroids might enable a slow human migration outward that might never end.

Many of us have become convinced that every asteroid is a killer. That belief is a downer and the evidence contradicts it. However, that people are willing to believe something about anything as esoteric as remote rocks in space is interesting. It causes me to wonder whether people might be ready to sign up for a more hopeful vision of asteroids. Could we become as excited about the certainty that asteroids are a new frontier for exploration and the possibility that people might live among them as we are now about the remote chance that one might destroy us?