Planetary Landing Vehicles - System Basics
This article is about basic system requirements a planetary landing vehicle should fulfill in order to make successful landing. The past several decades numerous landing vehicles crashed, the most memorable to me being Beagle 2, which was lost on planet Mars. Recently several landers were lost too on the Moon - one of them was Beresheet, an Israeli lander.
So why is it that in the past few decades several of those landers didnât make it while the technology they were carrying was much more advanced than it was in the 1950s to 1970s, when space technology was still in its infancy?
Well, according to my view not enough dedication to the fundamentals and basics of landing systems could be the reason.
In the 1960s a series of landers made it to the Moon without too much hassle, among them NASAâs Surveyor program and then the Apollo program. Those were the days with focus and insight on the basics and fundamentals. Technology those days was fundamental and pretty much radiation resistant for the simple reason that there wasnât that much electronics in those landers - remember the highest high-tech in the Apollo landers was a âcomputerâ, which failed during Neil Armstrongâs descent. Nonetheless, after reboot Armstrong landed safely.
Nowadays engineers and scientists tend to loose focus on the basics and find themselves digging and debugging millions of lines of code.
Now, let us focus on two landers, Beagle 2 and Beresheet.
At first in 2003 everyone believed Beagle had crashed on Mars and was lost right away as nothing was heard from the lander anymore -- ESA quit listening after some time. So the question rose, what went wrong with Beagle 2?
In 2005 an inquiry report was published hypothesizing and speculating on what the problem couldâve been.
And then in 2015 ... all of the sudden Beagle was found. According to the Guardian Beagle 2 was found on the surface of Mars after a successful landing - yes, successful, you read that right - but couldnât communicate due to solar panels which didnât deploy (properly enough)!!! And that weakness was already pointed out in the inquiry report, section 5.4.8, last paragraph.
Yes, not properly deployed solar panels nicked Pillingerâs child, Beagle 2. And that raises questions about the design. Below is a picture clearly showing the joint or hinge of a solar panel.
The joint connects the solar panel to the body of the Beagle 2. This joint looks rather -- maybe too -- primitive and may very well be the cause of the blockage.
So they spent millions of dollars (or was it pounds) on a lander but then something goes wrong with the deployment of the solar panels?!
We all know that space is a hostile and rough environment, even for a space craft. The journey -- the ride -- can go accompanied with extreme vibrations for any craft and with Beagle on a very tight budget they may have been cutting back on the mechanical strength of the Beagle too much so to save money.
The whole Beagle story raises the uncomfortable thought: was it tested enough? Could the designers not have foreseen that one particular solar panel would not open? And if so, that is would block the antenna? Having a clear antenna to communicate is rather essential, and any scenario blocking the antenna should have been foreseen, tested for, and dealt with in advance.
Similar story with Beresheet. It crashed due to failing gyroscopes (yes in plural). It looks like all gyroscopes failed!? Usually one gyro can fail, but the remaining gyroscopes should survive, which wasnât the case here; they all failed! Or was there just one gyroscope after all?
Nonetheless, with Beresheet a significant amount of resources went to a particular part of the payload from which it is clear that it did not add any scientific nor any technical value to the mission. If that part of the payload wouldâve been left out and its corresponding financial resources re-directed to the fundamentals and basics (read gyroâs) of the lander, then Beresheet wouldâve made it for sure. Here too a critical inquiry would be appropriate, even more than in the case of the Beagle.
I canât get rid of the feeling that the designers of both landers failed to focus on the robustness of the basics of the lander. It is absolute known in space industry that all sorts of things can go wrong and that keeping clear the critical components, like antennas and gyroscopes, is something that shouldâve been on a checklist of âdesign for robustnessâ, or something like that.
I admit, the budget can be tight. However, one needs to prioritize and make a checklist with at the top the most important parts of your lander, in this case the basics and fundamentals of the lander itself. At the bottom of that checklist there are the accessories, very often being the scientific instruments, and at the very bottom stuff with no scientific or technical significance, which is then cut out first if budget restrains come into play.
So you devote the necessary resources to the basics and fundamentals in the lander so the agency can get proof of a successful landing. If then there are any resources left, those can be devoted to the accessories.
Devoting enough resources to the basics and fundamentals of the lander is of absolute priority. From the point of budget there can be no compromises with the accessories.
Very often resources that shouldâve been destined or dedicated to the basics and fundamentals of a successful landing are being drained away for the scientific part on the lander, or even worse for that part to flatter national status.
It is understandable that on a tight budget the line of compromise is drawn so that less resources go to the lander itself and more for the scientific instruments. Big mistake! Make no compromises! Basics and fundamentals of the lander itself must come first and must have absolute priority!
References:
Surveyor program
Apollo program
Beagle 2
Inquiry report
Guardian
Beresheet
M.N.