FLO: The First Lunar Outpost

FLO Base Lander

One of two landers for the First Lunar Outpost, this an unmanned one with an adapted Space Station module on top for use as a place to live during the mission. The astronauts would arrive at roughly the same time aboard a manned lander. This picture is somewhat incorrect in that the real lander would have had two large solar panels stretching to the right and left. Public domain image from NASA.

What is was: A 1992 benchmark mission for NASA to return to the Moon, using expendable launchers and a direct descent lander, and build a small periodically-inhabited lunar base on the Mare Smythii.

Details: Early during the presidency of George H. W. Bush, the White House directed NASA via Vice-President Dan Quayle to come up with a plan to go to Mars—a goal announced to the public as the Space Exploration Initiative (SEI). To say that NASA botched this opportunity is to put it mildly.

Their (admittedly non-mandatory) orders were that NASA should come up with a plan that could get to Mars relatively cheaply, probably using technology that had developed since the end of Apollo. Instead they put forward an obvious relative of von Braun’s 1969 Mars Expedition, ditching the nuclear rockets but otherwise following the path of building a big space station, a permanent Moon base, and then finally moving on to Mars. The total cost of the program was estimated to be about US$540 billion over about thirty years—or, to put it another way, a rough doubling of NASA’s annual budget through the next several presidential administrations. This was political suicide and the whole thing collapsed in acrimony almost the moment it was put forward. Richard Truly’s career as NASA administrator came to an end in large part because of the fiasco and he was replaced by Dan Goldin in 1992.

Goldin’s mantra for NASA was famously “faster, better, cheaper” and he arranged for another study that would attempt to recover the manned lunar exploration part of the SEI. It was explicitly to be based on new ideas from the so-called Stafford Report (properly known as America at the Threshold: Report of the Synthesis Group on America’s Space Exploration Initiative) from the previous year. Out of this study grew the First Lunar Outpost (FLO) proposal.

Comet rocket for FLO

An artist’s rendition of the proposed HLV for the mission, referred to informally as Comet. Public Domain image from NASA.

The first step to the outpost was literally getting there. The initial SEI plan had foundered in part because of its allegiance to the Space Shuttle which, as it could lift only 25 tonnes to LEO, meant that NASA needed to build their Moon craft in Earth orbit; that in turn required a space station. FLO was based on a return to an expendable launch vehicle, and it would have been a monster: the core of the launcher would either be an all-new rocket or a stretched version of the Saturn V (to the extent that that program could be revived 20 years after its end); either would have been flanked with two boosters. Its resulting payload to LEO was to have been in the vicinity of 200 tonnes. Contrast that with the Saturn V at 118 tonnes, or 88 tonnes for the Energia.

This massive increase in capability was to be used in two ways: the Moon craft would not have to reconfigure itself in Earth orbit like the Apollo arrangement did, and it would land directly at its destination on the Moon rather than sending down a landing craft followed by a lunar orbit rendezvous before returning to Earth. As well as making the missions safer by allowing more ways to abort and opening up more of the lunar surface for exploration, this simplicity was believed to be the route to a cheaper mission despite the upfront cost of the rocket that launched it.


The FLO spacecraft on top of its TLI stage in Earth orbit. Public domain image from NASA.

Nuclear thermal engines were studied for the trans-lunar injection stage of the FLO spaceship, but it was assumed that it would probably use a J-2S LOX/LH2 engine—essentially the same as was used by the Apollo S-IVB injection stage, though slightly upgraded to use a de Laval nozzle. The lander itself would have used four RL-10s, repurposed from the tried-and-true Centaur.  Again, these choices were made with an eye to saving money by using what the American aerospace industry already had to offer.

The direct-descent/direct-return profile of the actual landing forced the lander to be quite different, though. Admittedly a scaled-up version of the Apollo CM was perched on top of it, where it would carry four astronauts in the relative comfort of 11.3 cubic meters—somewhat larger than the old CM and LM taken together. Below that, though, was a much bigger spacecraft.

It would have packed no less than ten propellant tanks, four smaller ones in an upper tier for the ascent stage, and six larger ones underneath for the lander itself. Sitting on a relatively robust landing truss and four very long legs the whole arrangement would have been 56.7 tonnes with propellant, which is more than four times the mass of the Apollo LM. It would have towered 14.1 meters above the lunar surface, and been 18.8 meters from landing-leg foot to landing-leg foot.

Another big change from the Apollo program was actually a return to what had been planned for the original Moon landings post-Apollo 20. A second, unmanned lander would have been sent prior to the manned one and landed within an easy Moon rover drive, no more than two kilometers. Its entire ascent stage would be swapped out and replaced with a 35-tonne habitation module made in the manner of a Space Station Freedom module with as few changes as possible—again as a nod towards cost.


A sketch of the interior of the FLO habitation module on top of the unmanned lander Note the solar panels. Public domain image from NASA.

This module would have been the actual base. The crew of the manned mission launched in tandem with it would live there for 45 days, exploring the region within 10 kilometers using the aforementioned rover driven by astronauts, and up to 100 kilometers driving it by remote control from the habitat. The explorers would then return home to Earth but the base would not be closed up permanently. Powered by two solar arrays that brought the width of the base craft to just over 41 meters, the intention was that further groups of astronauts could be landed nearby as often as every six months and would find themselves with usable living quarters right away.


Leaving the Moon in the Ascent/TEI stage, leaving behind the landing stage. Public domain image from NASA.

Once the lunar surface mission was over, the astronauts would return to their original landing craft. Its central stack would ignite a hypergolic N202/MMH engine (hydrogen being too tricky to hold on to for 45 days on the lunar surface) and head directly for home. The final twist on the Apollo mission design would have seen the FLO capsule land on dry land, rather than splash down into the ocean.

By sticking as much as possible to technology they already had, or at the very least were already developing, the cost of the project to the end of the first landing mission was estimated at US$25 billion, with the unmanned base touching down around 2000 and the manned follow-up soon after. Just over half of this money would be for the development of the launcher and building three rockets. Even making allowances for the inevitable cost and schedule overruns, it was a remarkably different result from the original SEI.

What happened to make it fail: George H. W. Bush lost the 1992 presidential election and the Clinton administration was noticeably less interested in manned space exploration for its own sake. NASA reoriented itself toward keeping people in LEO, primarily building what had now become the International Space Station, and unmanned space probes beyond Earth orbit.

Extended manned lunar missions did creep back onto the agenda over the next few years, particularly as part of George W. Bush’s “Vision of Space Exploration” which pictured them as a test-bed for an ultimate Mars mission. But the discovery of water ice at the Moon’s south pole by the Clementine satellite in 1994 changed the nature of all future Moon base proposals by slewing them heavily towards using that water. Despite its generally innovative approach to a lunar landing, the First Lunar Outpost turned out to be the last gasp of an older paradigm for exploring the Moon.

What was necessary for it to succeed: This one is more speculative than most, but it’s interesting to consider the First Lunar Outpost in terms of what happened to Space Station Alpha in the same time period. The station came perilously close to cancellation and was only saved by a foreign policy decision: to turn it into the International Space Station, specifically in partnership with Russia in an attempt to absorb the time and skills of the Russian space engineers freed up by the collapse of the Soviet Union.

If you were looking to start an American make-work project in 1993 that capitalized on Russian expertise, a space station made the most sense. After all, Mir was beyond anything the United States had ever accomplished. But it’s not too hard to picture the busy-work being fulfilled by a different major space program. Since a manned Mars mission was out of the question due to expense, the relatively cheap First Lunar Outpost might have been the choice if the Clinton White House had been more interested in the inspirational side of space exploration than its nuts and bolts. They wouldn’t have been the first administration to feel that way.

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9 thoughts on “FLO: The First Lunar Outpost

  1. It seems rather odd, but FLO was actually the _small_ exploration plan. NASA’s 90-Day Study of 1989 was massive, with a Moon base and Mars mission. That was instantly unworkable and there was a food fight for the next several years on how to get to a smaller and more affordable exploration plan. FLO was what they eventually landed at. But by the time NASA was really working it out, the whole Space Exploration Initiative was dead for several years.

    One thing that I did not realize until many years later is that although FLO received relatively little press at the time (in places like Aviation Week and Space News), NASA was actually doing quite a bit of study of the architecture. They were holding engineering workshops and things like that. There’s a lot more documentation on FLO than you would suspect.

    • I normally wouldn’t write about a NASA benchmark mission, since no-one is seriously considering doing them — they’re a bit like the plans for fighting a war against the UK and Canada that the US has back in the 1930s, something to dust off if needed.

      But you’re right that FLO seemed to have been a bit more serious than that. I believe that Dan Goldin was angling toward retrieving *something* from SEI and wanted this to be it. Unfortunately for him he became NASA administrator about a year too late for it to happen.

      • I’m not sure this is Goldin. I think it’s Mike Griffin. He was brought in to be the head of exploration in (I think) 1991 and initiated several projects. I think that FLO was his effort to establish an early mission that was possible. One of the problems with the SEI program was that NASA pitched all of it at once, rather than small initiatives that they could accomplish.

        I think that FLO was well underway by the time that Goldin came in as administrator.

        • Hm, interesting. I had one source that said Goldin was responsible…I’ll have to track down another and see if it agrees or contradicts the first one.

          • All my FLO material is at the office. When I get there I’ll check the dates. But there were some engineering conferences and for some reason I think that there was one in March 1992. Goldin became NASA administrator in April. FLO was reported in Aviation Week in August:


            I think that the FLO studies started in 1991, in part in response to the Stafford “Synthesis Group” report.

            Goldin stayed over to the new administration (starting January 1993) and he spent a lot of time reorienting the space station and getting the Russians onboard. I believe that by 1993 he initiated a cheaper lunar mission architecture. That got a little traction, then died. Later around 1995 or so he initiated a secret study to see if it was possible to do a $1 billion lunar mission (no). Then NASA gave up on advanced exploration for the next 5-6 years.

  2. I checked. I have FLO material dating from early May 1992 to early 1993. The May 1992 thing would have been underway before Goldin came in during April 1992. I suspect that there is FLO material from even earlier. So it clearly predates Goldin.

    • Most interesting…thank you! When time comes to revise, I’ll change this entry to reflect this. “Goldin didn’t initiate the FLO, but he clasped it to his faster, better, cheaper bosom and wore it down to a nubbin.” Hmm, perhaps some better phrasing there….

      • I found more of my FLO material. It appears that the effort started in fall of 1991, although it was not called FLO at that time. They were just calling it general exploration stuff, but clearly the goal was to nail down the first part of the overall Space Exploration Initiative, and that was an early lunar landing. I need to find out when Griffin was named AA for exploration, but I’m guessing that this was his initiative.

        I have some material from late 1991, and then it seems like they ramped up the effort by April-May 1992. Because Goldin was newly named as administrator, it’s pretty clear that they were in preparation before he came in. There was a big workshop in (I think, will have to check) early May 1992 and I doubt that Goldin started that, it was probably in the works.

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