Updates Mars Science Laboratory (Curiosity)

[orb]

IIRC, escape velocity is 11.2 km/s.

Escape velocity isn't constant: [math]v_e=\sqrt{\frac{2GM}{r}}[/math].

It's just equal to 11.2 km/s on the surface (sea level) of Earth.


More on [ame="http://en.wikipedia.org/wiki/Escape_velocity"]Escape velocity - Wikipedia, the free encyclopedia[/ame]

Also in the same article they said that the RD-180 first engine is russian made? I couldn't find any reference on that either! I thought that the engine of the Atlas V was US made.

http://en.wikipedia.org/wiki/RD-180

 

[Keatah]

When this thing gets there, how is the sky crane gonna know where to drop the rover? For all that it matters, it might drop it right on the side of a rock and the rover will tip 90 degrees and go belly-up!

For that matter, what sort of measurements are taken, if any, by the cruise stage to precisely orient the capsule for targeting a specific crater? And does the entry module do any sort of active course correction up to the point where it lets go of of the sky crane?

 

[RGClark]

WOOOHOOO!!!:woohoo: Great launch!:thumbup:

That's what $2.5 billion will get ya.

Bob Clark

 

[T.Neo]

That's what $2.5 billion will get ya.

The launch alone didn't cost a whole $2.5 billion! That is the total program cost.

The cost for the launch vehicle was perhaps around $200 million. Perhaps it could cost $2.5 billion... if Atlas V launched once a year.

 

[Urwumpe]

When this thing gets there, how is the sky crane gonna know where to drop the rover? For all that it matters, it might drop it right on the side of a rock and the rover will tip 90 degrees and go belly-up!

For that matter, what sort of measurements are taken, if any, by the cruise stage to precisely orient the capsule for targeting a specific crater? And does the entry module do any sort of active course correction up to the point where it lets go of of the sky crane?

AFAIR, you select the landing ellipse already in a way, that you don't land in rough terrain. The rest of the targeting is also simply ground control. There is no fire and forget for Mars Rovers yet.

There are possibilities to make the landing radar and cameras select a good landing site automatically, but at least the radar part would inflate the rover mass a lot, since you then need a much more powerful and much more precise analog part for the radar. (Optics are more unreliable, but can be done just by software, that is why cameras had been used by previous Mars rovers for aiming for a good landing site and cancel horizontal velocity)

As long as even parachuting human soldiers can't always tell properly where they are landing and what landing site they are actually aiming for, I don't want to expect this from probes for relatively unknown planets.

What can look perfectly flat can be the most annoying place. And what looks really jagged can be a perfect landing site.

 

[Ajaja]

Just for fun, Orbiter MJD/RPOS/RVEL from HORIZONS state vectors for MSL:

BEGIN_ENVIRONMENT
  System Sol
  Date MJD 55891.661261574
END_ENVIRONMENT

BEGIN_SHIPS
MSL:DeltaGlider
  STATUS Orbiting Earth
  RPOS  5.578081991138332E+06 -6.906871560268437E+06 2.695492584292812E+06
  RVEL -1.927030868136834E+03 -6.026352229727855E+03 7.524103264241185E+03
END
END_SHIPS

 

[Codz]

I have to say this and Juno are the most exciting missions of the year for me.

 

[Wally]

I would love to have MSL cruise stage for Orbiter, unfortunatelly I couldn't find anything on Orbiter Hangar.

 

[Artlav]

That is one hell of a bold landing system.
Scary thing is, it would actually work.

 

[Urwumpe]

That is one hell of a bold landing system.
Scary thing is, it would actually work.

I am pretty sure it can work, I did some calculations lately on the stability of such systems, the key problem is just the altitude determination.

 

[Jarvitä]

I am pretty sure it can work, I did some calculations lately on the stability of such systems, the key problem is just the altitude determination.

The point is, by the looks of it that thing has an order of magnitude more possible failure points than the airbag system used by earlier lander missions. Something like it was tested by the Phoenix mission, but the crane adds a whole new level of complexity.

 

[Urwumpe]

The point is, by the looks of it that thing has an order of magnitude more possible failure points than the airbag system used by earlier lander missions. Something like it was tested by the Phoenix mission, but the crane adds a whole new level of complexity.

Not that much, it also removes some other failure points that existed in powered landers like Vulcan. The airbag system also had a few points, where failure was not an option, and the weight limitations had been pretty terrible, as well as the fact that you don't land with airbags, but gently crash. A rover that lands on airbags has to be much more sturdy as something that is landed by skycrane.

One big advantage is that the engines are on top (stability) and further away from the ground, preventing strong dust clouds.

 

[Artlav]

I mean, just making this all work is a huge effort, without the potential failure factors.

It took me over a year to make a quadrotor fly mostly straight for a dozen seconds, while they have a much more unstable thing flying a precise profile in an unknown environment completely unsupervised.

Respect.
People who made this landing work definitely deserve a lot of respect.

 

[Urwumpe]

Your quadrotor would likely fly straight much easier, if you hang a heavy weight below it. :lol:

If it flies at all then.

 

[boogabooga]

The landing hasn't happened yet....

 

[Urwumpe]

The landing hasn't happened yet....

Yes, and when it happens successfully, it will be a major success for NASA - and open the box for many more applications that are similar... eg autopilots for cargo helicopters. :lol:

 

[Keatah]

The SkyCrane is doing little more than "landing" above ground level. Hovering. All it needs to do is get the right altitude and remain in position. The technology to do this is decades old anyways. They did it with the Viking Lander and Phoenix. The difference here is those two craft stopped hovering immediately above the gound. The SkyCrane will continue hovering till the rover is released.

The technology to control the rocket jets is nothing new either. It reminds me of these things. Which, by the way, I wouldn't mind strolling into McDonald's with this following me.

http://www.youtube.com/watch?NR=1&v=LC97wdQOmfI

 

[boogabooga]

The technology to do this is decades old anyways. They did it with the Viking Lander and Phoenix.

And Mars Polar Lander, I assume...

 

[SiberianTiger]

I am pretty sure it can work, I did some calculations lately on the stability of such systems, the key problem is just the altitude determination.

How is it going to do that? Is there a gamma source and scintillation detector, like Cactus system in Soyuz has, or is it unusable at required ranges?

 

[Urwumpe]

How is it going to do that? Is there a gamma source and scintillation detector, like Cactus system in Soyuz has, or is it unusable at required ranges?

That is completely unusable for that range. Not sure what kind of radar they use on the MSL, but there are currently tests with millimeter-band radar systems on helicopters, since these radars are immune to dust, contrary to LIDAR, and still small enough to be integrated into a single LRU. And also have pretty good power consumption values for ranges below 10 km altitude.