Five Year Retrospective: Mars Pathfinder

An anonymous reader writes "Five years ago today, on September 27, 1997, NASA and the Jet Propulsion Laboratory began to lose communication with the Mars Pathfinder and ended its highly successful mission. The interview with Matt Golombek, Project Scientist, highlights Mars' warm and wet past. The still remarkable landing sequence, with first signal only 3 minutes after touchdown, seemed a rare combination of luck (bounced 16 times and landed on its base petal). Not mentioned, it cost less than the making of even a medium-sized Hollywood movie." NASA is getting ready to publish their future plans for deep-space missions.

Comments

Celestia

[ajs]

I have a hard time talking about Mars or any other space-related topic now and not thinking about Celestia, which I installed on my Linux-based-laptop last night and spent hours using to explore the solar system, nearby stars and distant galaxies. It's a breath-taking display of what computers should be all about, and IMHO should be a tool in every grade school and high school in the country, which is then used to generate the next wave of Mars and near-solor-system exploration interest!

Check it out, and enjoy!

Re:OT - Lost comm with Pathfinder?

[bwohlgemuth]

The Pathfinder lander used a set of rechargable batteries that were designed only to withstand the cold nights of Mars for 30 days. The fact that we got over 60 days of useful data from the lander is a testament to the craft's designers and builders.

The reason that both Viking landers were on for years was due to the RTGs (Radioisotope Thermoelectric Generators) which generated electicity from the decay of plutonium. NASA didn't want to launch RTGs again after the big debate of the Cassini mission (and yes, I know Pathfinder did have minute amount of plutonium located in certain places to keep the craft warm).

Re:Why did Pathfinder's batteries fail so quickly?

[uberdave]

According to the FAQ at mars.jpl.nasa.gov, the batteries were not rechargeable.

Re:What do they expect?

[LMCBoy]

That "rare combination of luck" comment was completely inappropriate and misleading. Of course the lander was supposed to bounce and roll around, that was its design, and it was brilliant.

Problem: How do you safely and cheaply deliver a somewhat fragile payload to the surface of Mars?

+ Rockets? Really expensive, both in terms of cash and (perhaps most importantly) payload mass.

+ Parachute? Martian atmosphere's too thin to slow the payload sufficiently.

+ Deployable glider wings? Really complicated, therefore prone to failure. Also see Rockets entry.

Their solution: do the best you can with a 'chute, then deploy a cocoon of bouncy airbags to cushion the impact. Let the lander bounce, safely shedding mv**2 each time, until it comes to a rest.

If it happened to land upside-down, it had a mechanism to right itself. However, it landed "jelly-side-up", which I assume is what the article poster meant by "rare combination of luck". Since this made no difference anyway, I fail to see the relevance.

Anyway, you can see cool images and animations regarding the entry, landing and deployment of Pathfinder here: http://mars.sgi.com/mpf/edl/edl1.html

space travel...

[Anonymous Coward]

I remember in the 70's getting one of the Sci-Fi pulps of the time (Galaxy? Somtething like that) which often had factual writings as well by some of the authors and scientists...

One of them was an article on interstellar travel, with some thought toward a hydrogen ram-jet style vehicle, but also nerva-style ion propultion, etc...

The author stated that for a small amount, like $10 per person in the US, or $1 for every person in the world, we could probably build a craft to get to the nearest star. Now, I'm not so sure those were realistic numbers back then, and I'm sure it would be more now (inflation)... and, of course, every person in the world couldn't afford $1 even (think starving population in africa)... but...

If NASA setup a donation site where people could donate money to specific projects... unmanned mars mission, manned mars mission, going back to the moon, space station, unmanned interstellar craft, etc... well, I'd be willing to bet that if you knew the money was going to that project they actually *might* stand a chance of getting some good funding for these projects.

I know for a fact that I would be willing to put some donations into the pot. I think with the continual budget cuts for NASA, we are in essence cutting off one of the *biggest* creators of new science and innovation we have. A *lot* of things came out of the space-race that have created new business in this country.

Its R&D. Unfortunately, I see way too often the way companies "cut the budget" in this country.. and often R&D gets heavily cut when they are in trouble, since its not an "income producer". They forget about *future* income... the innovations of today will be tomorrows profit items.

My own company really does not *have* an R&D department anymore. We developed some really neat things in the past.. etching optics and silicon wafers (better/flatter wafers make better/faster chips and raise the yield of that wafer)... laser diode arrays smaller than a penny that product *WATTS* of output power (I have a picture somewhere of one burning a hole through a block of wood).. I mean, *neat* stuff. The plasma etching got sold off, the laser diode stuff got sold off, the guys in research who worked on and developed them were given to the respective companies...

the research department, which used to be at least like 40 people is down to maybe 4 or 5. And I haven't seen any neat new technologies come out of them in a while.

The Mars Polar Lander Failure in STQE Magazine...

[antdude]

In Volume 4, Issue 5 (September/October 2002) issue of Software Testing & Quality Engineering Magazine (article is not online), there is an article about the Mars Polar Lander (MPL) Failure. It is on page 12. It talked about the design failure from this premature shutdown. It was an interesting read on what happened with the software that failed and how it was discovered. :)

Re:My "plan" to save NASA (or space exploring anyw

[Anonymous Coward]

High bandwidth data comes down from the Shuttle and Station all the time. Watch NASA TV during a ISS servicing mission (such as the one next week) and you'll see a lot of it. Some of the best images come from the cameras mounted on the helmets of spacewalking astronauts. They send a crisp picture of what the astronauts see... they are spectacular views. Also, IMAX cameras have been brought up to film shuttle and station activity, and the results are breathtaking.

Mars is a different story entirely. The bandwidth to Mars is tight because it's a long way away! Even the two rovers being launched to Mars next year will only send stills. They have friggen incredible cameras, but the bandwidth is far too low for full motion video.

There are a few reasons why bandwidth to Mars is tight. Mars spacecraft are usually solar powered and thus have weak transmitters. They have small antennae and are half an astronomical unit away. (An astronomical unit (AU) is the distance between the Earth and the Sun.) The Deep Space Network (DSN) antennae are used to communicate with them, but the DSN is also used to communicate with dozens of other spacecraft throughout the Solar System. So, each Mars spacecraft only gets bandwidth for a few hours a day.

If you want full motion video from Mars, you have a few options:

• Blow all your bandwidth on a short, highly-compressed crappy movie
  
• Place communications satellites in orbit around Mars as relays. The Mars Global Surveyor and Mars Odyssey spacecraft in orbit around Mars now do low-bandwidth versions of this. People at NASA have talked about putting high-bandwidth comm relays in orbit, but they would cost a couple of hundred million a pop. (The scientists would love the high bandwidth, too, though.)
  
• Build the Square Kilometer Array (SKA). The SKA is a proposed radio telescope with a total surface area of one square kilometer. (Like you couldn't guess from the name. :) The SKA is intended for radio astronomy, but it would kick all ass for deep space communications. It would allow full motion video from Mars w/ current lander transmitter powers and antenna designs. This is a roughly $1 billion project, and would do a heck of a lot more than talking w/ spacecraft. (That alone would make it worth it, though.)
  
• Develop robust, inexpensive deep space laser communications. This is a much harder problem than most people would guess. Lasers are sworn at around the world by scientists because of their need for constant babysitting... developing reliable spaceflight hardware around lasers with a couple of watts of power output will be a challenge. Also, the beam is small (tens to hundreds of kilometers in diameter) after travelling between Earth and Mars, so the beam must be carefully pointed. Its a hard but interesting set of problems, and would probably cost a couple of hundred million to develop into off-the-shelf components.
  

Hopefully that gives you some introduuction to the problems. They're not insurmountable, but they will take some work (and cash). Personally, I'd love to see full motion TV (or 1280x1024 :) from Mars!

Sincerely,
A friendly neighborhood astrophysicist