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from the will-the-next-mission-have-Polo-A-and-Polo-B? dept.
NASA CubeSats Steer Toward Mars
NASA has achieved a first for the class of tiny spacecraft known as CubeSats, which are opening new access to space. Over the past week, two CubeSats called MarCO-A and MarCO-B have been firing their propulsion systems to guide themselves toward Mars. This process, called a trajectory correction maneuver, allows a spacecraft to refine its path to Mars following launch. Both CubeSats successfully completed this maneuver; NASA's InSight spacecraft just completed the same process on May 22.
The pair of CubeSats that make up the Mars Cube One (MarCO) mission both launched on May 5, along with the InSight lander, which is headed toward a Nov. 26 touchdown on the Red Planet. They were designed to trail InSight on the way to Mars, aiming to relay back data about InSight as it enters the planet's atmosphere and attempts to land. The MarCOs were never intended to collect any science data; instead, they are a test of miniaturized communication and navigation technology that can blaze a path for future CubeSats sent to other planets.
[...] While MarCO-A corrected its course to Mars relatively smoothly, MarCO-B faced some unexpected challenges. Its maneuver was smaller due to a leaky thruster valve that engineers have been monitoring for the past several weeks. The leak creates small trajectory changes on its own. Engineers have factored in these nudges so that MarCO-B can still perform a trajectory correction maneuver. It will take several more weeks of tracking to refine these nudges so that MarCO-B can follow InSight on its cruise through space.
Previously: NASA Launches InSight Mission to Study the Interior of Mars
CubeSats -- En Route to Mars with InSight -- Snap Another "Pale Blue Dot" Image
(Score: 2) by VLM on Monday June 04 2018, @07:45PM (3 children)
The two year minimum is the usual NASA-speak much like the rovers where they're really sure it'll run 2 years but maybe it'll run 20 years who knows.
Very hand wavy if you can boost X to GTO you can boost about half that to Mars, so figure 5000 pounds to mars. And 794 pounds landed, almost 1600 inside its re-entry capsule thingy plus we could round up to 1800 or even 2000 for mounting framework and stuff. So they launched at about half capacity.
A partial explanation might be a typical Hohmann transfer orbit to mars is 9 months. You can burn a lot of fuel to get there faster, and they're getting there in 6 months. Why the rush? I haven't the faintest idea. I'm also too lazy to work the math on the impact to payload of a 2/3 the time of a Hohmann orbit.
Your cost is way off, its $20K/pound delivered at max load, but they put it on an immense hot rod of a booster so more like $50K/pound delivered given the booster was only half full.
As much as I love recreational conspiracy theories, the best I can come up with is they assumed the thing would be fatter and later than it was, so they stuck it on an absolute hot rod of a booster. That way they could launch a lighter mission later, or a fatter mission earlier. The mission was scrubbed one season because the seismometer was broken, so maybe that makes sense, come hell or high water a booster that huge would get it there even if they had to launch as late as July (note: I didn't verify the math, might not be correct about that, but yeah, twice the delta-V necessary would imply they could get there really fast)
I read up on it a bit and this is the only booster they can use with a restartable upper stage thats in production as of this century. There would have been other options last century. Why is the probe designed so light, then? no idea.
There's a lot of retcon work along the lines of they have to launch from vandenburg because of workload issues because the beast was supposed to be launched in 2016 but was delayed so someone used a time machine when they were designing it to determine it would be on a slipped schedule and therefore have to be very lightweight to get launched from vandenburg or some such. I guess if you want a conspiracy theory here's proof the project manager for the probe had access to a time machine when spec'ing the probe to be ridiculous light. Reality of course is that if it wasn't light they might be screwed until 2020 or 2022 season and they knew the odds of getting delayed could happen so make it light enough to squeeze it into the schedule in 2018 even from a "bad" launch pad and time.
Its surprising really that one limiter to space missions isn't money to build rockets or tech to build probes but reserved pad time to launch the darn things. Doesn't matter how cheap space-x makes a launch if you can only launch X times per year per pad. And if you think people bitch about supersonic flight try convincing some HOA-suffering mcmansion owners to put up with a new spaceport making daily moon launches or whatever. Good luck.
(Score: 2) by takyon on Monday June 04 2018, @08:45PM
SpaceX has 3 launch facilities lined up and is building its fourth:
https://en.wikipedia.org/wiki/SpaceX#Launch_facilities [wikipedia.org]
Launch pace was 18 launches for SpaceX last year, and 11 so far in 2018:
https://en.wikipedia.org/wiki/List_of_Falcon_9_and_Falcon_Heavy_launches [wikipedia.org]
They could reach as many as 28-29 this year. Or maybe they will add on a couple to hit 30 for PR.
At the top of the page is a breakdown by launch site.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by frojack on Monday June 04 2018, @09:43PM
The thing sits on right on top of the Centaur, (which is not the only re-start-able space engine), and has a fairing which it already shed long by the time they reach GTO. So most of the "extra weight" is accounted for already. Fuel for a longer burn to get past GTO is already baked into the cake.
That leaves the booster way way less than half loaded.
There's only been 8 Atlas V from Vandenberg and all but two of those were super Secret NRO missions. (One of the two exceptions carried NRO Cube sats beside a DigitalGlobe photo sat, the other a NOAA weather sat. All required the polar launch. If you launch from there you have to take the spook orbit route, or your downrange is too risky.
But if you wanted to put up some more cube sats for the military, what better cover could you find than a rocket with a spare bedroom and a couple cube sats of its own to confuse the radars?
There is nothing clogging up the launch pad at SLC 41 (canaveral), and nothing planned there till August 27. (This pad is used almost exclusively for Atlas launches since 2000).
(Lots of secret shit is launched from SLC 41, but not on the spook orbit.
No, you are mistaken. I've always had this sig.
(Score: 0) by Anonymous Coward on Tuesday June 05 2018, @02:13PM
More like they ordered a probe or rover that will last two years, and if it fails within the warranty period, the supplier gets to replace it on-site at their own cost.
Anyone would build things to last a lot longer than required under those requirements.