[HN Gopher] First Image from Sony Star Sphere Satellite Released
___________________________________________________________________
First Image from Sony Star Sphere Satellite Released
Author : Brajeshwar
Score : 59 points
Date : 2023-02-27 15:09 UTC (7 hours ago)
(HTM) web link (tlpnetwork.com)
(TXT) w3m dump (tlpnetwork.com)
| chaostheory wrote:
| It would be nice to pair this with PSVR2
| Eyght wrote:
| I guess at some point we should expect a Sony SpaceStation.
| Evidlo wrote:
| How can they constantly reorient the spacecraft for each shot
| without quickly running out of propellant?
| Evidlo wrote:
| Nevermind, I guess they only need to use the gyros for changing
| attitude.
| mlyle wrote:
| Just a nitpick: they are reaction wheels (which work on the
| basis of conservation of angular momentum), not gyros (which
| work on the effect of gyroscopic precession).
| _a_a_a_ wrote:
| Could you explain further please.
| mlyle wrote:
| Angular momentum is conserved. If you're in space, and
| subject to no outside forces, and start off stationary...
| while you spin a wheel one way, you move in the other way
| (an equal and opposite _reaction_ ). When you stop the
| wheel, you stop. These are called reaction wheels.
| (There's also reaction spheres, etc.).
|
| A control moment gyro works on a different principle.
| They're big (generally only used on space stations) but
| more versatile and power efficient. They are a wheel
| spinning quickly. A motor "tilts" the wheel and the
| resultant gyroscopic force imparts a torque to the
| station.
|
| https://en.wikipedia.org/wiki/Control_moment_gyroscope
|
| https://en.wikipedia.org/wiki/Reaction_wheel
| _a_a_a_ wrote:
| Very interesting, the reaction wheel is obvious but to
| the gyro is not.
|
| I can't see any efficiency problem though, electrical
| spin-up and spin-down with regenerative braking should
| reclaim the energy. I'll read the wiki article. Thanks.
| mlyle wrote:
| > I can't see any efficiency problem though, electrical
| spin-up and spin-down with regenerative braking should
| reclaim the energy.
|
| A lot of uses of reaction wheels requires them to
| constantly spin because there's been an outside force
| applied. The wheel mass also tends to be low because it's
| divided between multiple axes and so speeds of wheels
| need to be pretty high.
| detrites wrote:
| Does this mean you'd always need three reaction wheels
| (or possibly just two?) to be able to orient in any
| direction, or is a single wheel itself able to orient to
| face different directions before activation, to achieve
| the same thing?
| mlyle wrote:
| Two wheels, or a movable wheel, or a "ball" that you can
| actuate in two directions do it.
|
| Of course, you probably also have thrusters (to "spin
| down the wheels" when they accumulate speed from outside
| forces), magnetorquers, passive stabilization mechanisms,
| etc.
| detrites wrote:
| Magnetorquers, very interesting - electromagnets that
| couple with the earth's magnetic field to assist with
| attitude/stabilisation:
|
| https://en.m.wikipedia.org/wiki/Magnetorquer
| mlyle wrote:
| Yup. There have even been satellites that have used only
| passive stabilization--- a permanent magnet + dark/light
| surfaces that spin it up from photon pressure.
| hughes wrote:
| It likely has reaction wheels and magnetorquers on board for
| attitude control. The propellant is only used for orbit
| raising.
| 7952 wrote:
| I think you also use propellent to reset the reaction control
| wheels when they run too quickly.
| dylan604 wrote:
| raising and lowering. sometimes, you have to move your bird
| out of the way of something else. with enough notice, you
| speed up or slow down to change altitude cost effectively.
| direct lifting in altitude is expensive in use of fuel
| flerchin wrote:
| Well that seems to substantially ease restrictions on space
| photography. I assume the project is in response to the rule
| change that allows US satellite imagers to be approved if
| commercial images are available of the same type from another
| country. https://spectrum.ieee.org/eased-restrictions-on-
| commercial-r...
| zokier wrote:
| Not really. Airbus, a french company, is already providing
| high-quality satellite imagery. Based on the specs and the
| sample pic, I don't think this Sony thing is going to provide
| any useful imagery; its more of a fun artsy marketing campaign
| thing than something for serious use.
|
| Just a month ago there was a startup announcement reselling
| satellite imagery to low-volume customers, and it raised fairly
| big comment thread. That thing has far better chance of
| democratizing satellite access
| https://news.ycombinator.com/item?id=34468644
| Rebelgecko wrote:
| >offering an unprecedented opportunity for users to select one of
| 16 possible orbits, each of which can be completed in
| approximately 90 minutes.
|
| Does the satellite actually change orbits for every user? That
| seems super expensive, propellant-wise. Or just 16 different
| tracks from the earth's precession?
|
| Also, I'm not sure if this is actually the first satellite that
| let regular people take their own satellite pictures -I believe
| Ardusat aka Nanosatisfi aka Spire previously let people rent the
| cameras on their cubesats
|
| Edit: actually I'm not sure if Ardusat ever actually let users
| use the camera feature
| renjimen wrote:
| Most satellite imagery companies (Planet, Maxar, Satellogic
| etc.) allow users to pay for "tasked" imagery over an area
| within a given time window. This article doesn't explain why
| this Sony effort is the first of its kind in that regard.
| adolph wrote:
| _Sony describes its Star Sphere project as a way to open space
| perspectives that have been previously limited to just astronauts
| and provide it to anyone on Earth via remote-controlled orbiting
| camera satellites._
|
| https://petapixel.com/2023/01/05/sony-star-sphere-will-let-y...
| modzu wrote:
| "anyone on earth" might exclude those who cant pay the fee
| of...
| shiftpgdn wrote:
| Yes but now instead of having to spend $20 million on a
| satellite launch (including R&D time and hardware, not just
| the rideshare fee) you can pay $XX dollars to get your photo.
| Seems to be a significant cost savings.
| pixl97 wrote:
| I'm sure users from nations embargoed by whatever nation
| these images are sold from.
| zokier wrote:
| "Currently, this service is available only at Japan and
| United States"
|
| https://starsphere.sony.com/en/
| KingLancelot wrote:
| [dead]
| [deleted]
| detrites wrote:
| HNHTD, here's the archive.org link:
|
| https://web.archive.org/web/20230227151050/https://tlpnetwor...
| z2210558 wrote:
| "HNHTD"?
| talos wrote:
| HN hugged to death?
| detrites wrote:
| 434F5252454354.
| [deleted]
___________________________________________________________________
(page generated 2023-02-27 23:01 UTC)