ESA's Jupiter-bound Juice spacecraft has a sticky problem with its radar A tiny pin stuck in place on ESA's Juice spacecraft may be preventing engineers from unfurling its 16-metre-long antenna as it zooms toward Jupiter. Launched two weeks ago, the probe just started its eight-year voyage to the largest planet in our Solar System to take a closer look at the Jovian moons first spotted by Galileo …
...how many of the people involved in these long term probe missions have in the back of their minds the likelihood that Starship will, over the next few years, make it much, much cheaper to send probes on higher velocity orbits and send newer, better and bigger probes that will get there faster merely by being able to boost a cheaper more fuel-filled probe into orbit for much less money.
A pint or three of barley Juice for everyone involved, it's still great science and engineering :-)
Nah. To get gravitationally captured, the amount of velocity you need to lose when you get to Jupiter depends largely on the size of the mismatch between your orbital velocity and Jupiter's.
See https://en.m.wikipedia.org/wiki/Porkchop_plot for a rough introduction to the mechanics of where you can go when, when you are flying mostly directly to your destination.
JUICE is taking a long time to get to Jupiter because its path involves a lot of gravity assists to get there. It also uses a lot of gravity assists from the Jovian moons in order to get captured by Jupiter.
More delta-v gives you more options about where to go when. Gravity assists are very cheap in terms of delta-v but take a very long time.
Bigger rockets give you only marginally more delta-v because the rocket equation has a logarithm in it.
I just think that having an onboard camera capable of snapping pictures of the probe itself is a good idea. There have been many occasions over the decades when I wondered why this hadn't been done, especially since the things are incredibly small and cheap these days and as engineers said things like "we're pretty certain x is the problem, but we can't know for certain because we can't actually see it". In terms of probes, the obvious example is an earlier Jupiter mission - Galileo - where the high gain antenna failed to deploy fully, reducing the capacity of the downlink quite considerably. Engineers determined that a few specific arms of the folded antenna had got stuck and devised shaking operations to try to free them. It's possible that with a proper photograph of the thing, other information might have been available, but instead all we had were artists impressions of the problem (this looks like something done much later).
M.
Generally the very small and cheap camera's really don't have the resolution and dynamic range to tell you anything useful in the "either too bright too see anything unless you have a tiny aperture and super short exposure time, or so dark you won't see anything" environment of space. On top of that it's not just the camera, it's cables to connect them, interface boards to connect them to the computers and whatever peripherals (software and hardware) needed to make them work. All of which add mass and power requirements to the probe, all of which add components that can complicate shaker tests, all of which add components that can fail in all kinds of interesting ways. We're slowly seeing more and more engineering camera's rolled out on spacecraft, but they're always going to be very strategically and sparingly placed and spacecraft designers are going to be very hesitant to add too many of them. Certainly to get a camera on a problem like this you'd probably need it to be either absolutely tiny and moving with the radar antenna setup or on some sort of complicated movable contraption to position the camera somewhere it can see anything. Both of which will very conservatively estimated add several years worth of engineering effort to a spacecraft just for the luxury of maybe, potentially having some extra pictures if something unexpected fails, but nearly entirely useless for the mission science if everything goes as planned.
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