7 ms·
It would be great to see some startups work on interplanetary video streaming tech. If you're building an other video streaming service, stop what your doing, a
by krm01 6y ago
It would be great to see some startups work on interplanetary video streaming tech. If you're building an other video streaming service, stop what your doing, and give this a try. I know I know. Very, very hard to solve and all, and this is totally a fanboy speaking, but it would have been awesome if we could have seen this footage in (as close as possible to) real-time when the landing happened.
- djxfade 6y agoSo, the minimum delay between Mars and Earth is around 11 minutes, usually higher. And the bandwidth is something like 60 MiB/Sol. This is just totally unrealistic with any known tech for the foreseeable future
- apendleton 6y agoCurrent delay is ~11 minutes, but minimum is much lower (~4 minutes, per https://blogs.esa.int/mex/2012/08/05/time-delay-between-mars-and-earth/ https://blogs.esa.int/mex/2012/08/05/time-delay-between-mars... ). We were last at that closest point in October, and the various voyages (this one, UAE's Hope, China's Tianwen-1) were timed so the closest pint was during the transit; we're a bit past it now.
- giantrobot 6y agoNothing about "interplanetary streaming" needs to be invented. The limiting factor is the size and power of the transmitter on Mars (or wherever). The MRO orbiter for instance is the highest bandwidth probe we've sent to Mars and it maxes out at about 4Mbps when Mars is closest to Earth. When Mars is farther it can only do about 500Kbps. That relatively prodigious rate requires the use of 34m receiving antennas on Earth. So if you wanted to stream video from a GoPro on a Mars orbiter you could do so with current technology, you'd just need to build some big-ass antennas on Earth and then build and launch the Mars orbiters. Besides being technically difficult (because rocket science) it would be really expensive.
- kbaker 6y agoMaybe that's what Elon has planned for the back side of the Starlink v2.0 satellites - to create an Earth-sized massively distributed phased array and get a super-high-bandwidth downlink from Mars.
- giantrobot 6y agoWow. That's not how any of that works.
- CompuHacker 6y agoOh, do explain a little more about why that doesn't work; wavelengths, total power, distances, etc.
- giantrobot 6y agoLet me enumerate the ways. 1. Starlink satellites have Ku and Ka transceivers for uplink and downlink. They simply aren't capable of talking to any Mars probes using X band radios for Earth communications which is all of the current and near future ones. 2. A phased array can use beam forming to "aim" and to use aggregate receivers for resolution but they're seeing limited. Tiny receivers on Starlink satellites (even arrayed) would be no good for Mars probes even if they covered the right bands. 3. Every element involved in the question is in motion relative to every other element. Starlink satellites have orbital periods of about 90 minutes. Each satellite would only have Mars visible for at best half its orbit. With Mars effectively a point source any Starlink satellites arrayed to receive signals from Mars would need to rotate in sync to keep Mars in view. That necessitates pointing all a satellite's other antennas away from each other and Earth since they're all bus mounted. This means they can't simultaneously do Starlink and Mars relay tasks and you'd need a lot of Starlink sats to even begin to effectively receive Mars transmissions.
- craftinator 6y ago"You are wrong and should feel bad! I rest my case!"