Nov 22, 2019 02:32 AM
(This post was last modified: Nov 22, 2019 03:20 PM by C C.)
SpaceX has lost its first Starship prototype—is this a big deal?
https://arstechnica.com/science/2019/11/...-big-deal/
EXCERPT: . . . So what's the deal? Is this a catastrophe for SpaceX that dooms its Starship program? Or just a minor setback as the company suggests? The answer is probably closer to the latter. The key to grasping why SpaceX can afford an accident like this is to understand its iterative design philosophy. Under this approach to the design of spaceflight hardware, the company builds vehicles, tests them, and flies them as quickly as possible. And if they fail, as often happens, SpaceX fixes them.
[...] This "fail early, fail forward" strategy allows a company to move more quickly and improve its design along the way. It also results in public failures, such as the all-explodey rocket Wednesday. This cannot exactly strengthen customer confidence in Starship, but given that failures are baked into the development process, it does not diminish Starship's overall prospects.
For casual observers of spaceflight, this "iterative" design philosophy is very different from the much slower, linear design process used by traditional aerospace partners for large development projects. Under this more traditional process, a company—or, historically, NASA—seeks to avoid the risk of a rocket failing before it is perfected. Years are spent designing and testing every component of a vehicle before it is assembled for a full-scale test. As a result the process is much slower and more costly... (MORE - details)
Other countries and companies are planning their own (potentially irresponsible) massive satellite constellations, so focus on SpaceX specifically is kind of moot in terms of avoiding a disaster to astronomy. Barring laws and standards being enacted quickly, with all the international communities accepting them.
This Is How Elon Musk Can Fix The Damage His Starlink Satellites Are Causing To Astronomy
https://www.forbes.com/sites/startswitha...85f6314ccc
EXCERPT: . . . If Elon Musk's Starlink project continues as it has begun, it will likely end ground-based astronomy as we know it. [...] SpaceX, under the guidance of Elon Musk ... plans to initially deploy 12,000 satellites in a mega-constellation known as Starlink. Ultimately, the constellation hopes to extend to a total of 42,000 satellites. As of November 20, 2019, only 122 of these satellites have been deployed, and they've already had a detrimental impact on astronomy on a global scale. If we hope to mitigate this, either regulators or SpaceX executives themselves will need to mandate a change.
[...] On November 18, 2019, a series of 19 of these Starlink satellites passed over the Cerro Tololo Inter-American Observatory's site in Chile, lasting for more than 5 minutes and heavily affecting the wide-field DECam instrument, which images a field containing 3 square degrees at an outstanding 0.263 arcsecond-per-pixel resolution.
Even though this only represents 0.3% of the total number of proposed Starlink satellites that SpaceX wants to launch, the consequences are clear: wide-field astronomy designed to look for faint objects — prime goals of observatories like Pan-STARRS, LSST, and any observing program geared towards finding potentially Earth-hazardous objects — is going to be significantly hindered. Averaging over frames is not a desired option, because it erases astronomers' ability to study the natural variability of astronomical targets, another important science goal. Because Starlink satellites autonomously change their orbits and are extremely radio-loud, ground-based observations cannot be scheduled so as to avoid them.
In addition, not all of these satellites will wind up in traditional low-Earth orbits, which will decay and fall back to Earth on timescales of months, years, or (at most) decades. While the current batch is going to 550 km, some are slated to remain at elevations of over 1,000 km, where orbital decay will take millennia. Already, back in September, the ESA's Aeolus satellite (used for Earth observation) had to make an emergency maneuver to avoid colliding with a SpaceX Starlink satellite, despite the fact that it was SpaceX's responsibility to move.
[...suggestions...] 1.) De-orbit the current batch of Starlink satellites, and place a moratorium on the launch of new ones until the proper modifications have been made... 2.) Either redesign or coat the satellites to significantly reduce their reflectivity... 3.) Provide real-time trajectory plans, predictions, and adjustment information for each satellite to observatories worldwide... 4.) Provide funding to assist astronomers in the development of hardware and software-driven solutions to subtracting out as much of the satellite pollution as possible.
[...] Right now, the Outer Space Treaty only prohibits the militarized use of space; all peaceful purposes are allowed. There are no consequences for damages done to the night sky and no regulations on pollution or contamination. So long as you register your satellite(s) and don't cause an in-orbit or on-Earth collision, there is no legal liability to what you do. The astronomical community's only options are either to attempt to get laws passed protecting the night sky, or to hope that the industry will self-regulate. ... (MORE - details)
https://arstechnica.com/science/2019/11/...-big-deal/
EXCERPT: . . . So what's the deal? Is this a catastrophe for SpaceX that dooms its Starship program? Or just a minor setback as the company suggests? The answer is probably closer to the latter. The key to grasping why SpaceX can afford an accident like this is to understand its iterative design philosophy. Under this approach to the design of spaceflight hardware, the company builds vehicles, tests them, and flies them as quickly as possible. And if they fail, as often happens, SpaceX fixes them.
[...] This "fail early, fail forward" strategy allows a company to move more quickly and improve its design along the way. It also results in public failures, such as the all-explodey rocket Wednesday. This cannot exactly strengthen customer confidence in Starship, but given that failures are baked into the development process, it does not diminish Starship's overall prospects.
For casual observers of spaceflight, this "iterative" design philosophy is very different from the much slower, linear design process used by traditional aerospace partners for large development projects. Under this more traditional process, a company—or, historically, NASA—seeks to avoid the risk of a rocket failing before it is perfected. Years are spent designing and testing every component of a vehicle before it is assembled for a full-scale test. As a result the process is much slower and more costly... (MORE - details)
Other countries and companies are planning their own (potentially irresponsible) massive satellite constellations, so focus on SpaceX specifically is kind of moot in terms of avoiding a disaster to astronomy. Barring laws and standards being enacted quickly, with all the international communities accepting them.
This Is How Elon Musk Can Fix The Damage His Starlink Satellites Are Causing To Astronomy
https://www.forbes.com/sites/startswitha...85f6314ccc
EXCERPT: . . . If Elon Musk's Starlink project continues as it has begun, it will likely end ground-based astronomy as we know it. [...] SpaceX, under the guidance of Elon Musk ... plans to initially deploy 12,000 satellites in a mega-constellation known as Starlink. Ultimately, the constellation hopes to extend to a total of 42,000 satellites. As of November 20, 2019, only 122 of these satellites have been deployed, and they've already had a detrimental impact on astronomy on a global scale. If we hope to mitigate this, either regulators or SpaceX executives themselves will need to mandate a change.
[...] On November 18, 2019, a series of 19 of these Starlink satellites passed over the Cerro Tololo Inter-American Observatory's site in Chile, lasting for more than 5 minutes and heavily affecting the wide-field DECam instrument, which images a field containing 3 square degrees at an outstanding 0.263 arcsecond-per-pixel resolution.
Even though this only represents 0.3% of the total number of proposed Starlink satellites that SpaceX wants to launch, the consequences are clear: wide-field astronomy designed to look for faint objects — prime goals of observatories like Pan-STARRS, LSST, and any observing program geared towards finding potentially Earth-hazardous objects — is going to be significantly hindered. Averaging over frames is not a desired option, because it erases astronomers' ability to study the natural variability of astronomical targets, another important science goal. Because Starlink satellites autonomously change their orbits and are extremely radio-loud, ground-based observations cannot be scheduled so as to avoid them.
In addition, not all of these satellites will wind up in traditional low-Earth orbits, which will decay and fall back to Earth on timescales of months, years, or (at most) decades. While the current batch is going to 550 km, some are slated to remain at elevations of over 1,000 km, where orbital decay will take millennia. Already, back in September, the ESA's Aeolus satellite (used for Earth observation) had to make an emergency maneuver to avoid colliding with a SpaceX Starlink satellite, despite the fact that it was SpaceX's responsibility to move.
[...suggestions...] 1.) De-orbit the current batch of Starlink satellites, and place a moratorium on the launch of new ones until the proper modifications have been made... 2.) Either redesign or coat the satellites to significantly reduce their reflectivity... 3.) Provide real-time trajectory plans, predictions, and adjustment information for each satellite to observatories worldwide... 4.) Provide funding to assist astronomers in the development of hardware and software-driven solutions to subtracting out as much of the satellite pollution as possible.
[...] Right now, the Outer Space Treaty only prohibits the militarized use of space; all peaceful purposes are allowed. There are no consequences for damages done to the night sky and no regulations on pollution or contamination. So long as you register your satellite(s) and don't cause an in-orbit or on-Earth collision, there is no legal liability to what you do. The astronomical community's only options are either to attempt to get laws passed protecting the night sky, or to hope that the industry will self-regulate. ... (MORE - details)