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Historical Spaceflight / Oldest functioning space probes
« Last post by nicp on Today at 12:19 pm »
Voyager 2 is usually considered the oldest functioning space probe.
However, I recall Pioneer 6 was contacted in 2000 (see Wikipedia here: https://en.wikipedia.org/wiki/Pioneer_6,_7,_8,_and_9 )

That article states "there has been no contact since December 8, 2000. At this time Pioneer 6 had operated for 12,758 days, making it the oldest operating space probe until it was surpassed by Voyager 2 on August 13, 2012. It is also believed that contact is still possible with Pioneer 7 and 8; only Pioneer 9 is definitely not working."

Which begs the question - are there other probes out there that still function if only they were contacted?
I understand why they aren't - newer and shinier probes are out there and tracking is an expensive and limited resource.
But I'd love to know if one of the old Mariners or probes of similar age still function.

EDIT: Lose the Wikipedia tags.
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SpaceX Starship Program / Re: The Starbase pilgrimage thread
« Last post by rsdavis9 on Today at 12:10 pm »
With all the infamy that Boca Chica's mud holds, it sounds like someone could do a roaring trade in personal hovercraft rental.

High tide kayak rentals? That's my usual way to get into places bounded by fences on one side and water on the other.

Just be aware of the weather,  tide tables and especially the trespassing regulations. For example, in my home state anywhere below the low tide line is normally public property as long you stay in the water (really fraks off the 1-percenters who built right to the waterline), but some waters can be declared closed by the state and federal governments (LNG terminals, nuke beaches, government installations, etc.).

In my state of New Hampshire the public has rights to the high tide line. It really surprises the rich land owners when you kayak over their lawn at a high tide.
Maine right next door uses low tide for ownership.
 
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SpaceX Starship Program / Re: The Starbase pilgrimage thread
« Last post by laszlo on Today at 12:05 pm »
With all the infamy that Boca Chica's mud holds, it sounds like someone could do a roaring trade in personal hovercraft rental.

High tide kayak rentals? That's my usual way to get into places bounded by fences on one side and water on the other.

Just be aware of the weather,  tide tables and especially the trespassing regulations. For example, in my home state anywhere below the low tide line is normally public property as long you stay in the water (really fraks off the 1-percenters who built right to the waterline), but some waters can be declared closed by the state and federal governments (LNG terminals, nuke beaches, government installations, etc.).
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Shuttle History - Pre-RTF / Re: Shuttle Sunday Shows
« Last post by Chris Bergin on Today at 12:02 pm »
STS-2, 3 and 4.

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Shuttle History - Pre-RTF / Shuttle Sunday Shows
« Last post by Chris Bergin on Today at 12:01 pm »
STS-1:

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As this is in the news again I figured I'd go look for pictures, video or *anything* that gives us an impression of what it is.. can someone save me the effort?

I thought I did. The second post in this thread has a link to the complete patent application, including 20 pages of illustrations starting on page 51 of the pdf file. Figure 21 (page 65) is a drawing used to 3D print a 9-bladed test article. Figure 26 shows the thing built with triangular electrodes. Figure 29 shows a carbon nanotube implementation.

Only effort needed is to read the 1st 2 posts, follow a link and click. Have fun.
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Blue Origin / Re: New Glenn 3-Core Version
« Last post by edzieba on Today at 11:49 am »
"There's three rockets. You glue them together. How hard is that? Well, according to my team, it's really hard." -- Gwynne Shotwell
but how hard is it if you don't refuse to use existing industry knowledge?
Still really hard, you just have a grizzled veteran engineer to tell you it's really hard.
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Primary launch opportunity = 2024-04-22 23:10:00 UTC per CelesTrak. (Presumably delayed from 22:40 because of weather.)

https://twitter.com/TSKelso/status/1782315792325071246

Quote from: T.S. Kelso
CelesTrak has pre-launch SupGP data for the @Starlink Group 6-53 launch from Cape Canaveral on 2024-04-22 at 23:10:00 UTC: https://celestrak.org/NORAD/elements/supplemental/table.php?FILE=starlink-g6-53. Deployment of 23 satellites 2024-04-23 at 00:15:06.340 UTC. Data for 6 backup opportunities also provided: https://celestrak.org/NORAD/elements/supplemental/.

https://celestrak.org/NORAD/elements/supplemental/

Launch: 2024-04-22 23:10:00 UTC. Deploy: 2024-04-23 00:15:06.340 UTC.
Launch: 2024-04-22 23:34:00 UTC. Deploy: 2024-04-23 00:39:06.340 UTC.
Launch: 2024-04-23 00:44:00 UTC. Deploy: 2024-04-23 01:49:06.340 UTC.
Launch: 2024-04-23 01:10:00 UTC. Deploy: 2024-04-23 02:15:06.340 UTC.
Launch: 2024-04-23 01:26:00 UTC. Deploy: 2024-04-23 02:31:06.340 UTC.
Launch: 2024-04-23 02:28:00 UTC. Deploy: 2024-04-23 03:33:06.340 UTC.
Launch: 2024-04-23 02:40:00 UTC. Deploy: 2024-04-23 03:45:06.340 UTC.
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Rotating detonation engines are over-rated. None of them have demonstrated even mediocre performance, yet.

The detonation is just another way of trying to get a higher effective combustion pressure. A good pump system is at least as viable.
The point of RDREs is not increased efficiency or performance: turbomachinery-pumped engines can already get pretty close to the theoretical limits there. The point of an  RDRE is to achieve the same combustion pressures and temperatures without the turbomachinery, giving you an engine with the mechanical complexity and (similar) mass of a pressure-fed engine but the performance of a turbopump engine. Improved TWR with fewer moving parts.
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Space Science Coverage / Re: NASA - Chandra X-Ray - spending cuts
« Last post by hoku on Today at 10:33 am »
<snip>
The are a couple of strategic questions here.
<snip>
3/ What is the relative importance of different wavelenghths?
The relative scientific importance of different wavelength regions is open for discussion. A physical fact is that a large fraction of the electromagnetic spectrum are blocked by Earth's atmosphere, and that astrophysical signals reaching ground-based observatories are degraded by, e.g., atmospheric seeing and atmospheric emission. Short-wavelength observations of the extreme UV, X-rays and gamma-rays require space-based observatories.

The US community also has access to the ESA-led XMM-Newton, which has a larger collecting area, but worse angular resolution than Chandra. Like Chandra, XMM was launched in 1999. Its operation is currently funded through 2026, with another 3-year extension until 2029 being anticipated. The International X-ray Observatory (IXO), a joint NASA-ESA-JAXA follow-on mission, was cancelled by NASA in 2012. Athena, the ESA-led "replacement" for IXO, recently went through a major crisis, with "New Athena" now expected to launch not earlier than the late 2030s.

https://science.nasa.gov/mission/xmm-newton/

https://en.wikipedia.org/wiki/International_X-ray_Observatory

https://asd.gsfc.nasa.gov/athena/
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