For Jeff King: Why are Interplanetary Robots So Expensive?

One of the downsides to having multiple blogs all on the same system is that I sometimes put my post on the wrong blog. This was first put on Rocket Scientist (where The Mother commented: "Two words: R and D." It should have obviously been put here. Sorry about the confusion.


Jeff King asked: The mars rovers look simple to build, so why do they cost so much to build… actually I thought they would look cool and very complex?

That's actually an excellent question. I think a lot of people wonder how space equipment comes to be so very very expensive. And it is. Even simple straightforward equipment is often an order of magnitude more expensive than it would be in a retail outlet.

There are several reasons for this, but those reasons are driven by two other reasons: extreme environment and reliability. The first reason drives design and it's easy to underestimate the impact of environment on hardware.

To rove around on Mars, a vehicle has to be able to withstand dust and unknown terrain.

It must be able to withstand a radiation environment that is far harsher than we have on Earth (thanks to the protection from our magnetic field), which is hell on electronic equipment, computers and data storage. Most electronic hardware made to withstand high radiation environments are created for military and frequently go through extensive testing and/or "rad-hardening" that exposes them to radiation, testing and often redesign so that they can reliably withstand more extreme radiation environments. This not only increases development and testing time, it might increases material costs if different materials are required to reach an effective design. That increases costs enormously, especially given that there are often only a handful of vendors for a part - which means they can charge nearly anything they want for those consumers who must have them.

The electronics and batteries and all other equipment must also be able to withstand temperature extremes, particularly cold which is very hard on many aspects, including lubricants, batteries, electronics. The extreme in cold can affect tolerances for mechanical interfaces. Which means all equipment must be tested in environments colder than most electronics on this planet need to survive for months if not longer. Vacuum (or, rather, the very very low pressure) adversely affect lubricants as well and complicate thermal characteristics as convection effects are limited. That means you might need some form of heating and cooling for electronics that are cold-sensitive or heat-producing.

For reliability, there are design considerations as well. The design has to be restartable and redundant, in case something goes wrong, or the cost of the whole mission (hundreds of millions, mostly on the trip to/from) is lost. Batteries must be lightweight, high density, resilient to radiation and cold, reliable, and long lasting. Solar arrays must also be lightweight, efficient, reliable and able to use the reduced light available on Mars (compared to here).

Because so much hinges on the functionality of these parts, each part must have a "pedigree" - i.e. been obtained through vendors that have certified processes and materials and who ensure that each part is tracked and verified to be clean and functional. And that makes those parts more expensive.

But, what frequently costs so much is verification and analysis. Hardware is tested, exhaustively, through dedicated use (often months) in testing facilities. Often flight-like prototypes are destructively tested to ensure the flight hardware meets requirements. In addition, a great deal of time and manpower is spent performing reliability and safety analyses, fracture control analyses, fault trees and failure mode and effects analysis, safety assessments.

Frequently, complex (and it can look simple without being simple) devices are one-of-a kind and require exhaustive and unique software that must also be exhaustively tested and retested.

No one's going to sue us if a rover fails, but years of design and planning, years of flying through space, and, literally, hundreds of millions of dollars are at stake, not to mention quite a few reputations.

If it's gotta work, you gotta do it right the first time and that costs a lot of money. But it's cheaper than doing it over. Better more money spent on testing than a second flight because the first one failed.

And that's why they cost so much.

And kudos, I think, have to be offered to the teams that built both Opportunity and Spirit for surviving >20X their expected lifetimes. That design overkill meant we got our money's worth.

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Hiatus Interruptus - For Jeff King: Where Will We Go?

Jeff King asked: If we ever travel to a planet, i mean actually going there ourselves in a spacecraft. What one do you think it would be, and when?

Well, do you count the moon? 'Cause, in my opinion, that's the way to go.

Why, you might ask. Because the moon is close at hand, an excellent place to test out all the things we're going to need when we move to other planets. Any other planet is months (if not years) to get to, a complicated trip where, if anything goes wrong, there are limited options to correct the rescue them. If the US doesn't make it there in the next ten years or so, other countries are also considering it and they will go there first.

However, if the moon doesn't count, it will be Mars. Why?

First, although Venus is technically closer, it is very inhospitable. Hot - I mean DAMN hot, toxic atmosphere, high pressure (like deep underwater type pressure). Right now, we just don't have equipment that can protect people from this kind of harsh environment. Protecting people from vacuum and temperature extremes found in "deep space" is child's play next to protecting people from temperatures that will melt lead (literally) or exposure to sulfur dioxide.

The gas giants are very very far away with no place to land. Some of the moons to the gas giant have possibilities as places to explore. But, as for planets, Mars will be first.

When? Not sure. It depends on when we come up with the right plan and then DO it. Not soon enough.

Now returning me to my regularly scheduled hiatus.

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For the Mother: Tell Me About Mars Exploration

The Mother gave me a great question since I was out of them: What is the current status of the manned mission to Mars? Loved the "Mars Rising" series. How much of that was true?

This is a great question, most of which I can't answer, because the answer to the first part is "speculation status" and the answer to the second one is "I have no idea because I've never seen it." I really should watch a little television once in a while, but I really don't. But fear not, I think you'll like my whole answer anyway.

To elaborate on the first answer, let me explain. Constellation (our exploration program) is designing hardware to launch (Ares I rocket) a craft (Orion spacecraft) capable of going to and from the ISS and orbiting the moon in support of lunar expeditions and outposts (like excursions only longer on the order of months). I believe there are groups actively starting to wrestle with the challenges associated with building the lander (Altair) for the Moon. These are the criteria we are using for the design even though a manned mission to Mars is definitely an end-goal.

But, right now, there's a world of speculative prototyping and speculating on the right directions to take for both the lunar surface and, especially, Mars. Some of the prototypes exist and are quite cool, though perhaps not as cool as the many concepts being bounced around in simulations. Some of those are supercool. But Mars is at least twenty years away and what we actually find is most practical, what we actually build and fly so far away may resemble the concepts out today as much as street cars match automotive concept cars. A lot can happen between now and then, a lot of politics and money wrangling, a lot of lessons to learn on the moon, a lot of technology to perfect. The plan is to use the designs we're designing now as the starting point for Mars, but by then, there's no way to tell how much we'll be able to use moving forward. Everything you saw in the documentary might be true, but I'd bet a great deal of it will look different when we really get there.

So, why not design for Mars now?

I'm glad you asked. (You would have, you know it).

Well, first, we're not ready.

• Part of it is that we haven't sent people beyond low earth orbit in literally decades. We need to reteach ourselves learning from what was done before and taking advantage of some of the technological advances since then (like computers - Apollo 11's computer had a total of 80 Kb - not Gb, not Mb. I think my watch has more than that. I know my cellphone does.) Most of the people who were deeply involved in the Apollo Program are either retired or dead. We haven't been building those kinds of rockets, those kinds of spacecraft in decades.
• Part of it is that we don't know enough. Mars has had many missions to it, but we still don't know it as well as the moon but there's a lot we don't know about the planet and the trip there. Even more importantly, what we do know poses technological problems we don't necessarily have the knowhow to fix today.
  
• Additionally, there considerable challenges to address that we don't have with the moon. Like a lander than can deal with reentry. Like storms. Like a long long trip with no one able to come rescue you if something goes wrong. And things go wrong with Mars missions, quite frequently. Roughly two thirds of all planned Mars missions failed before completing their missions. Not because of a bogeyman, but because getting there is complex, is challenging, is tricky with minimal margin for error. And, if we fail, we only lose money, not people. We'd better know what we're doing before we send people are sent over. Just the radiation and meteoroids alone are issues.

That's why going to the Moon is so important. It's a dry run for most things we have to do for Mars, but within reach. The math to reach the moon is relatively benign and we don't have those tricky three month launch windows. There's no complicating atmosphere and no storms, BUT it has gravity and we haven't waltzed in spacesuits in gravity for years. It has a high radiation environment (relative to low earth orbit) and methods we develop there to protect the crew may help with Mars. We'll want to explore it with rovers and there's no reason to think we can't test out real designs in a real extraterrestrial environment to see how they work. Dust mitigation on the moon will be at least as challenging as it will be on Mars and we better get that handled because, if we come back with an enclosed environment as dusty as the Apollo missions came back, we'll have a whole lot of astronauts with red lung.

It gives us a relatively safe way to prove we have a viable program because, if things go wrong here, it might be days or weeks before we can get them, but it won't be months and years. Mars has a 780 day period between 2-3 month windows for optimized approach. We can launch one vehicle in that period, but, if something goes wrong after the window has gone by, anything we send after them has no possible way to catch up - heck they won't be going to the same place. The earth has changed positions and so has Mars. We may have no choice to abandon them, alive or dead. If they get lost on the way, if they get stranded on Mars, help can't reach them, even if we were able to launch immediately for months or years. Maybe ever. We need to be confident, really confident, they can make it before we send them.

Or, let's say, we send two during the window and we find out, say, when the first lands, that there's a catastrophic design flaw with the lander. We'll either have to waste the second mission's trip and send them back or we'll have to gamble that the second lander can survive. The moon can help increase our confidence in our hardware.

Personally, I like the design I've seen of the rover they're talking about. It's a pressurized rover with suits you climb into from the back but they're attached to the outside. This eliminates the need for an airlock, drastically reduce dust brought into the habitable environment and is way safer for the astronauts in my opinion. Here's hoping that our end result is as appealing as they current model (pictured above and below).

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