Water-hunting NASA cubesat won't reach Moon after total thruster fail

A tiny NASA cubesat, sent to hunt for signs of water ice on the Moon, will not reach lunar orbit after all four thrusters in a miniaturized propulsion system malfunctioned en route. The Lunar Flashlight satellite was launched on 11 December with a planned four-month journey to look for hidden ice around the lunar South Pole. …

[JassMan]

If the job is important, neverruse untested technology

"The spacecraft was kitted out with a miniature propellant system never tested before running on a relatively new type of propellant dubbed Advanced Spacecraft Energetic Non-Toxic (ASCENT) by the US Air Force"

The could take a tip from aircraft builders. When you are testing a new propulsion system, use a multi-engined vehicle that has flown reliably for years and just replace one engine with your new one.

OK, it was a good idea to use 4 thrusters for redundancy, but if they are all identical, the chances are that if one fails they will all fail unless there is an external event such as a meteorite strike.

[Gene Cash]

Re: If the job is important, neverruse untested technology

No, the 4 thrusters are not redundant. They're pointing in different directions.

A big part of the job was testing the propulsion system. They got an unexpected answer, but they at least got an answer, and can try to figure out what happened based on the data and make a decision on what to do.

This is a technology demonstrator and it's done its job. That's why it's a cheap little cubesat and not a large real satellite. Version 2.0 will probably be tested on another cubesat.

I'm sure they're disappointed about the state of things, but they didn't spend a huge heap of money on it, and they still learned something.

They're still going to get to test the Lunar Flashlight bit anyway.

[M.V. Lipvig]

Re: If the job is important, neverruse untested technology

Version 2.0 - same system, but with a remote control pipe cleaner to wiggle into the thruster ports. You know, to clear the debris.

[JassMan]

Re: If the job is important, neverruse untested technology

"No, the 4 thrusters are not redundant. They're pointing in different directions."

If it has one thruster in each direction along with a tried and tested gyro system for altering the sats orientation (which it does), that makes for quadruple redundancy. The big problem is that gyros take a long time to change attitude and this results in the loss of manoeuvrability at the time when you need it most at the end of the journey.

[yetanotheraoc]

Re: If the job is important, neverruse untested technology

"one thruster in each direction"

I thought there were six directions in a cube.

[AVR]

Re: If the job is important, neverruse untested technology

Four on a tetrahedron will do the 3D job.

[John Brown (no body)]

Re: If the job is important, neverruse untested technology

According to the article, it's not a tetrahedonsat, it's a cubesat,, so not helpful to remind the designers that they built it with too many sides and/or not enough thrusters :-)

[yetanotheraoc]

Re: If the job is important, neverruse untested technology

With 5 upvotes and 1 downvote, it looks like one of the thrusters is pointing in the wrong direction.

[lglethal]

Re: If the job is important, neverruse untested technology

Replacing one engine on an existing aircraft to test it costs effectively nothing, as the aircraft is not a single use item. Unfortunately, a satellite is. So you can go larger and significantly more expensive (majorly more) and have two propulsion systems and make sure it gets where it wants to be, or you can go "cheaper", whilst certainly not cheap, use only one propulsion system, and do a shit ton of pre-testing on Earth, and accept the risks.

That's what they did in this case, and it failed. But it's highly likely they would not have the funding to build the satellite in the first place if they went with the dual propulsion system, so now they will get at least a little bit of data for their efforts, as opposed to none, due to a lack of funding. It's still a win, and they will definitely have learned some stuff about the new propulsion system, and not just the age old adage "Space is hard"...

[Christoph]

Re: If the job is important, neverruse untested technology

I gather the point was to test smaller, lighter engines. Putting three bigger heavier engines in probably would not have fit in a cubesat?

[Sceptic Tank]

You miniaturized that pipe a bit much

NASA declined to say how this will aid them in the search for life on other planets.

[Anonymous Coward]

Re: You miniaturized that pipe a bit much

"NASA declined to say how this will aid them in the search for life on other planets."

...but this CubeSat was only looking for the signs of WATER and not LIFE - which would be a totally different mission - plus it would need a lot more fuel to go searching other planets.

(PS: If it had been looking for life, then they could just stay in Earth orbit and look towards the planet surface and see if there's any life on Terra Firma ?).

[Anonymous Coward]

Re: You miniaturized that pipe a bit much

Unless you are looking specifically for intelligent life. Don't see much of that around anymore.

[Muscleguy]

Re: You miniaturized that pipe a bit much

The clangers got the soup dragon to fly up and breath soup down the thruster pipes.

[DS999]

If its a "cubesat" I assume it this was a pretty low budget project?

Probably smart for NASA to try to some less important projects using cheap satellites to compare with the big budget stuff that has a mission life of 5 years but ends up lasting for the better part of 50. Might be that they need multiple cheapskate launches to insure success, but that's still probably much cheaper. Save the high budget stuff for the more public facing, or "one in a lifetime" projects like Voyager being able to gravity assist to reach all the planets.

[John Brown (no body)]

Re: If its a "cubesat" I assume it this was a pretty low budget project?

Agreed. It was on a 4 month journey too, so a low fuel orbit, reducing fuel cost and overall mass, so yes, a cheap, relatively speaking, mission.

[Jan 0]

Re: The goal was to reach a near-rectilinear halo orbit (NRHO) around the Moon,

Following that link through to the next link, still doesn't explain the term.

The cubesat is being put into an elliptical (or near elliptical) orbit!

AFAIK rectilinear still means "straight line" and the "nearness" is that one part of the orbit gets close to the Moon's South Pole!

[zuckzuckgo]

Re: The goal was to reach a near-rectilinear halo orbit (NRHO) around the Moon,

A halo orbit does not strictly speaking orbit the moon. It orbits one of the Lagrange points. In this case I assume the L1 point between the earth and the moon. From the earth the orbit looks like a halo around the moon. Its path is influenced by both the earth and the moon and is unstable so thrusters are needed to make occasional corrections. I take it that the near-rectilinear aspect is that when it passes closest to the moon it is travelling in a near straight line - at least straighter than a purely elliptical orbit.

[s. pam]

looks like a case of...

Premature Propulsionation....

i'll get me coat

[Potemkine!]

a miniature propellant system never tested before running

Not even on Earth? If so, sounds risky.

[cuthbertgraak]

Lunar Flashlight gone T.I.T.S.U.P.

Totally Inhibited Thrusters Seized Under Pressure