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95 votes
Accepted

Why A=2 and B=1 in the call signs for Spirit and Opportunity?

On MER we numbered the builds, but used letters for the launches. So MER-1 was built before MER-2. MER-A would both launch and arrive first, and MER-B would launch and arrive second. When we started, ...
Mark Adler's user avatar
  • 58.2k
27 votes
Accepted

Why did NASA's Soujourner Mars rover die at the same time as Pathfinder?

The only way for the Soujourner rover to transmit data to Earth or receive commands from Earth was through the Pathfinder lander. If Pathfinder died, Sojourner was also essentially dead.
David Hammen's user avatar
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24 votes
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Why did Spirit (MER-A) lose a wheel?

No explanation has been established for the wheel failure, although a motor brush failure is one possibility. Source: Mars Exploration Rover Spirit End of Mission Report
Organic Marble's user avatar
23 votes
Accepted

Why do the more recent landers across Mars and Moon not use the cushion approach?

Propulsive landing is now a proven technology and a factor of 1,000 more accurate. According to NASA Facts; Mars Exploration Rover: With the heat-shield portion of the aeroshell pointed forward, the ...
uhoh's user avatar
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23 votes
Accepted

How did the spirit rover land right way up after bouncing

Mars Pathfinder, Spirit, and Opportunity all could come to rest on any of four sides of the tetrahedral-shaped lander. Just by chance, Mars Pathfinder and Spirit landed with the base petal down. ...
Mark Adler's user avatar
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20 votes

Why wasn't robotic arm used to free Spirit rover from sand trap? (and other things...)

Answering the question in the title, because the arm could not reach anywhere but the front wheels. The description here indicates the left/right swing of the shoulder joint was 160 degrees, so the ...
GremlinWranger's user avatar
16 votes

Why do the more recent landers across Mars and Moon not use the cushion approach?

The 2007 paper The challenges of landing on Mars gives a decent introduction to the subject, and the evolution of Mars landing methods. First generation: Viking. Propulsive landing, lander on legs. ...
Hobbes's user avatar
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10 votes

Why wasn't robotic arm used to free Spirit rover from sand trap? (and other things...)

I actually received a reply from NASA when I sent this question to them at the time. Unfortunately I can't find the exact email anymore, but their official reply was that the motors in the arm were ...
Innovine's user avatar
  • 4,625
7 votes

What were Spirit and Opportunities wheels made out of?

Aluminum and foam according to this page that describes the wheels as manufactured from a single Aluminum block with foam inserts into the spiral suspension system spokes. The black surface of the ...
GremlinWranger's user avatar
6 votes
Accepted

Do Mars rovers have irises? How do they safely look at the Sun?

They use neutral-density filters to look at the Sun, which reduce the light by a factor of 100,000. The two Pancam cameras each have one neutral-density filter, with the left one filtering blue and ...
Mark Adler's user avatar
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6 votes

Have any systems on any Mars rovers failed (even partially) as a result of a dust storm? (besides loss of solar power)

Not specifically during a single storm, but: One interesting case of a partial failure of a system is that of the optical calibration targets on Opportunity, Spirit and Curiosity. They were ...
Jack's user avatar
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6 votes
Accepted

How did Spirit and Opportunity identify ferric sulfate and jarosite on Mars?

Reference [1] describes the finding of jarosite in the Mawrth Vallis region of Mars. The NASA Mars rovers include IR spectroscopy in their instrumentation, and that was the method used. The finding ...
Oscar Lanzi's user avatar
  • 8,525
6 votes

Why was a nuclear battery system not used for the Mars Spirit and Opportunity rovers?

Mars Spirit and Opportunity rovers exceeded expectations by working for many years than the planned 90 day mission. Ninety days was not the planned mission. It was instead the bare minimum amount of ...
David Hammen's user avatar
  • 75.1k
5 votes

Why wasn't robotic arm used to free Spirit rover from sand trap? (and other things...)

Found specification of all the motors of the IDD (robotic arm): https://esmats.eu/esmatspapers/pastpapers/pdfs/2003/fleischner.pdf Rover mass is 176.5 kg A mass "m" produces a vertical ...
jumpjack's user avatar
  • 3,043
5 votes
Accepted

Why was a nuclear battery system not used for the Mars Spirit and Opportunity rovers?

Spacecraft design is based on conservative, pessimistic estimates, "stuff that's proven to work". When those estimates are (usually) exceeded, the next generation "faster horse" ...
SE - stop firing the good guys's user avatar
4 votes

Which images were used primarily for navigation algorithms on the Spirit rover?

What you're looking for is the images from the "Navigation Camera". As explained here, the mast-mounted stereo imagers collectively referred to as the "Navigation Camera" were used for navigation. ...
called2voyage's user avatar
  • 23.7k
3 votes

Can either Opportunity or Curiosity explore the state of Spirit?

I know this is a dead thread but let me go ahead and point out that 1. Opportunity is out of action, hopefully temporarily 2. We wouldn't want Curiosity OR Opportunity to get in the same situation as ...
Ryan's user avatar
  • 31
3 votes
Accepted

Why is it so important to visit Columbia Hills in Gusev Crater again?

Gusev crater is a former outflow region at the base of the Eridania basin (marked with the black contour in the image below). This region has recieved renewed attention and interest recently, after ...
AtmosphericPrisonEscape's user avatar
2 votes

Why is it so important to visit Columbia Hills in Gusev Crater again?

Rescuing a rover isn't the purpose, Spirit is dead for all intents and purposes. Rather, Spirit found it to be a very interesting area, and the desire is to continue that investigation. The key seems ...
PearsonArtPhoto's user avatar
  • 121k
1 vote

How to retrieve MER2 Spirit rover orientation along the traverse map?

Position I found the answer for position. The only kernels needed for the https://wgc.jpl.nasa.gov:8443/webgeocalc/#StateVector are the ones included in "main MER release" in the list: Then ...
jumpjack's user avatar
  • 3,043
1 vote

How to obtain 3d data from MER Spirit "Planetary Data System" products/files?

The xyz file is in the format "PDS image data" according to the file command; GDAL may understand it. We can rule out ...
David McKee's user avatar

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