Jonathan Amos

My last story as a staffer for the BBC. A puzzle that surrounds the end-of-life manoeuvres of the oldest UK satellite still up there - #Skynet1A. Who moved it, when and why? bbc.co.uk/news/articles/…

This is pretty cool. @SurreySat has been engaged to develop the spacecraft platform for the Lazuli space observatory, which is Eric and Wendy Schmidt's idea for a privately-built telescope with a primary mirror larger than Hubble's.

@ByJoshLewis Some of the ways these bergs melt and fracture can inform us about the ways ice shelves could also collapse when confronted by warmer waters and air. Already, we've seen ponding surface melt water leading to hydrofracture on Antarctic Peninsula shelves. e.g. Larsen B in 2002.

@JCDAmos Seems very odd for the researchers to compare this to Antarctica proper, which will not move around, let alone so far north into hotter waters

Not quite RIP, but maybe last breaths. The BBC's Mark Poynting and Erwan Rivault catalogue the life and times of Iceberg A23a: bbc.co.uk/news/resources…

It's hard to believe it was once so big. See Erwan's comparison map below. The US National Ice Center will soon stop cataloguing and tracking the old giant.

Every day now brings another blowout. This image from Nasa/Terra/Modis comes from yesterday (6 March). As Mark and Erwan point out: at 48 deg South, the iceberg is nearer the equator than London.

Iceberg A23a crosses the 49th Parallel South and suffers another big fragmentation event. Now only 170 sq km. Still bigger than many British cities but a far cry from the 4,000 sq km behemoth that broke free from Antarctica in 1986.

@Will4Planet @Rob_Coppinger @FT @Google One more to add to the list. Upper-atmospheric pollution from space debris re-entry. It’s an emerging issue that industry needs to grapple with some urgency.

Great to see @FT exploring the complexities of orbital data centres & our work w/ @Google on Suncatcher. Just a quick response here. Generally, space-based AI is a lofty goal, but it's a more sustainable long-term solution in comparison to terrestrial alternatives. Absolutely true that all the components take real Earth resources, but one does not need: 1) buildings, 2) land, 3) water cooling; & with simple 24/7 solar power, 4) large battery plants or nuclear/fossil power stations to get continuous power. 🌍 Most of the specific issues raised, we already know how to solve: - Cooling: this is the hardest bit, but we cool devices in space all the time with passive & active radiators. It drives mass but the calcs show it's altogether cheaper in space with launch <$200-300/kg, which we estimate is coming in just 2-3 years <-- hence starting now. - Space debris: agreed, we have to take care but we do know how to avoid this, mainly by flying in low, 'self-cleaning' orbits. - Radiation hardening: advanced computers perform very well for many years in orbit. We need to test TPUs, but unlikely to be a roadblock. - Servicing: one doesn't need it; we'll just accept a small failure rate. - Monitoring: much easier in space than terrestrially: neither launches or orbital objects can be hidden, unlike underground buildings. - Astronomy interference [my add]: we need to take care not to ruin observations from ground-based telescopes. Luckily we'll use dawn-dusk polar orbits, which reduces this significantly. In sum, lots of complex issues to tackle, but all look tractable. This is a Moonshot, but its an idea whose time has come... 🛰️🖥️💫

Iceberg A23a lost a 1/4 of its area on Sunday. Image left is from Saturday. Image right is today. Now just 315 sq km and surrounded by the spreading melange from Sunday's sudden collapse. Notice how quickly the ramparts corralling surface meltwater have reformed.

The remnant iceberg A23a has suffered another massive hydrofracture event at 46 deg S, 32 deg W. You can just make out the slush puppie splurge of melange around a central block of robust ice. Not long now. This image is from @eumetsat Meteosat-12 at 11:20 UTC on Sunday.

Iceberg A23a today (17 Feb). A totally clear sky. Utterly stunning. Still refusing to die. Still 500 sq km in area. Image from the Modis instrument on the venerable Aqua satellite, another oldie that's still plugging away.

📢Oxford Space Systems Wrapped Rib Antenna Successfully Deployed In-Orbit on CarbSAR Mission aboard @SurreySat .Proven, compact, stowage-efficient antennas enabling high-performing Earth Observation - UK SAR 🔗Full details here: oxford.space/post/?permalin…

Radarsat provider @Iceye proposes 1,000-sat network including SAR/optical, RF-sensor &transport layer for European govts. Several billion euros - within current EU/ESA budgets, says CEO. Initial service 2028, ops by 2030 feasible. Just an idea. #defis_eu @esa #Europeanspaceconf

Wonderful view of A23a and it's latest two daughters, created in that massive hydrofracture event on the weekend of 10/11th. All three retain copious volumes of meltwater on their surfaces. These really are end days now. Thank you @SEN

These subtle ripples have revealed the presence of thousands of previously unknown hills, valleys, ridges and ancient river systems. New paper in @ScienceMagazine from Helen Ockenden et al science.org/doi/10.1126/sc…

The landscape hidden beneath Antarctica's ice sheet has been mapped from space for the first time. Scientists used hi‑res satellite observations to track how the continent’s frozen surface bunches and dips as it moves over the rugged rock bed below. bbc.co.uk/news/articles/…

One big paddling pool becomes three. Today's view of iceberg A23a (left) and a view from the end of December (right). Notice how the raised rim effect, holding in surface meltwater, has re-established on all three segments of the broken berg. A23a is turning to slush puppie.

💥 Boom! And it's just happened. The huge volumes of meltwater that had collected on the surface of iceberg A23a have triggered a massive and catastrophic hydrofracture event. Much of the berg has turned to mush. Three major segments remain, the largest about 500 sq km.

Remember back in the day when OneWeb Gen 2 was going to be a platform for British industry, for sovereign PNT and all sorts of UK hosted payloads? What exactly did $0.5bn of UK taxpayers' money buy? Another of the great 🇬🇧 missed opportunities.

@mouthofmorrison I will be hiding behind several cushions.

@JCDAmos You are not prepared for how violently antennas deploy under zero g

We have AOS - Acquisition of Signal. The Knitted Satellite, aka CarbSAR, is talking to Earth after a successful SpaceX launch on Sunday. Next step is to release the wrapped rib antenna. It should happen this week. There are cameras to record the release. newscientist.com/article/251084…