Hvordan ville en realistisk rumkamp se ud?

Science fiction rumfilm kan gøre et dårligt stykke arbejde med at oplyse folk om rummet. I filmene, hot-shot piloter dirigerer deres duellerende rumskibe gennem rummet, som om de flyver gennem en atmosfære. De banker og drejer og udfører sløjfer og ruller, måske smide en hurtig Immelman-sving, som om de er underlagt Jordens tyngdekraft. Er det realistisk?

Ingen.

I virkeligheden, en rumkamp vil sandsynligvis se meget anderledes ud. Med en stigende tilstedeværelse i rummet, og potentialet for fremtidig konflikt, er det tid til at tænke over, hvordan en faktisk rumkamp ville se ud?

Den non-profit Aerospace Corporation mener, det er på tide at overveje, hvordan en rigtig rumkamp ville se ud. Dr. Rebecca Reesman fra Aerospace Corporation's Center for Space Policy and Strategy og hendes kollega James R. Wilson har skrevet et papir om emnet rumkampe, med titlen "The Physics of Space War:How Orbital Dynamics Constrain Space-to-Space Engagement."

Hvis tidligere menneskelige anliggender indikerer fremtiden, så vil militariseringen af ​​rummet fortsætte. Det er på trods af snak om at holde rummet fredeligt, og på trods af traktater, der siger det samme. Så det er vigtigt, at efterhånden som flere nationer vokser deres tilstedeværelse i rummet, og efterhånden som en konkurrence om ressourcer begynder at skabe problemer, at samtalen omkring rumkonflikt tager en realistisk drejning.

Det er det, forfatterne gør i introduktionen til deres papir. "Når USA og verden diskuterer muligheden for, at konflikten strækker sig ud i rummet, det er vigtigt at have en generel forståelse af, hvad der er fysisk muligt og praktisk. Scener fra Star Wars, bøger og tv-shows skildrer en verden, der er meget anderledes end den, vi sandsynligvis vil se i de næste 50 år, hvis nogensinde, givet fysikkens love."

Der har aldrig været en kamp i rummet endnu. Men der har været en del våbentestaktivitet. Kina arbejder på anti-satellit våben og har testet et anti-satellit missil. Det har Indien også. Rusland arbejder også på anti-satellitkapaciteter, og USA gør det samme. USA ødelagde faktisk en af ​​sine egne satellitter med et missil tilbage i 1985.

Dette er sandsynligvis kun toppen af ​​isbjerget, når det kommer til fremtidig konflikt i rummet. Ingen af ​​denne anti-satellit aktivitet involverede mennesker, der rejste i rumfartøjer, og der vil måske aldrig være behov for bemandede militære rumfartøjer, ifølge avisen. "Rum-til-rum-engagementerne i en moderne konflikt vil udelukkende blive udkæmpet med ikke-bemandede køretøjer styret af operatører på jorden og stærkt begrænset af de begrænsninger, fysik sætter for bevægelse i rummet."

I de tidlige dage af rumalderen, mens den kolde krig stadig rasede, supermagterne forestillede sig, at konflikt i rummet i høj grad ville være en forlængelse af jordiske konflikter. Sovjetterne designede endda rumstationer bevæbnet med et maskingevær til at forsvare sig mod angreb fra amerikanske astronauter. USA arbejdede på lignende ideer.

Men teknologiske fremskridt betød, at disse bestræbelser blev opgivet til fordel for ubemandede satellitter. "Til sidst, begge programmer vaklede. I stedet, forbedringer i teknologi og datatransmission - den samme udvikling, der i sidste ende understøtter vores moderne forbundne liv - muliggjorde satellitter, der udfører de samme militære funktioner, som var forudset for de tidligere besætningsprogrammer." rummet er domineret af satellitter, med kun ISS, der er vært for mennesker.

Dette bliver fremtiden, ifølge avisen. I de næste 50 år eller deromkring, enhver konflikt i rummet vil involvere angreb på satellitter. Men ikke alt vil være et direkte angreb. Forfatterne skitserer fire mål i et rumangreb:

• Bedrag en fjende, så de reagerer på måder, der skader deres interesser.
• Afbryde, nægte, eller forringe en fjendes evne til at bruge en rumkapacitet, enten midlertidigt eller permanent.
• Ødelæg fuldstændig en rumbaseret kapacitet.
• Afskrække eller forsvare sig mod en modangrebsmodstander, enten i rummet eller på Jorden.

Satellitter bevæger sig meget forudsigeligt. De bevæger sig hurtigt, men det er relativt nemt at forudsige deres fremtidige position og at opsnappe dem, i mange tilfælde. Nogle satellitter kan ændre deres banehøjde, men de har ingen reel manøvredygtighed og næsten ingen måde at undgå et angreb på.

"For at beskrive, hvordan fysik ville begrænse rum-til-rum-engagementer, denne artikel beskriver fem nøglebegreber:satellitter bevæger sig hurtigt, satellitter bevæger sig forudsigeligt, pladsen er stor, timing er alt, og satellitter manøvrerer langsomt."

At flyve gennem Jordens atmosfære er ikke ligefrem enkel, men det er ret intuitivt. Men i rummet, det er helt anderledes og kaldes ikke nøjagtigt flyvning. Uden atmosfære og lav tyngdekraft, tingene er meget forskellige. "Bevægelse i rummet er kontraintuitivt for dem, der er vant til at flyve i Jordens atmosfære og chancen for at tanke brændstof, " skriver forfatterne.

"Rum-til-rum-engagementer ville være bevidste og sandsynligvis udfolde sig langsomt, fordi rummet er stort, og rumfartøjer kan kun undslippe deres forudsigelige stier med stor indsats. Desuden, angreb på rumaktiver ville kræve præcision, fordi rumfartøjer og endda jordbaserede våben kun kan engagere mål i rummet, efter at komplekse beregninger er fastlagt i et meget konstrueret domæne." Der ville ikke være nogen kadre af jagerpiloter på standby, venter på at klatre og hurtigt starte. I stedet, en rumkamp, ​​der involverer satellitter, er mere en matematisk øvelse.

"This is true because physics puts constraints on what happens in space. Only by mastering these constraints can other questions such as how to fight and, mest vigtigt, when and why to fight a war in space, be explored, " de skriver.

A satellite's orbit is predictable because of the relationship between speed, altitude and the orbit's shape. At lower altitudes, satellites can experience atmospheric drag. Også, the Earth isn't a perfect sphere. But those factors can be accounted for in an attack. "To deviate from their prescribed orbit, satellites must use an engine to maneuver. This contrasts with airplanes, which mostly use air to change direction; the vacuum of space offers no such option, " de skriver.

The sheer volume of space is also a factor in a space battle. "The volume of space between LEO and GEO is about 200 trillion cubic kilometers (50 trillion cubic miles). That is 190 times bigger than the volume of Earth."

So tracking satellites accurately in that volume of space will be a continuous challenge, since some will be designed to be undetected. But that's not impossible; satellites are regularly tracked. And since they're not very maneuverable, once a satellite's orbit is detected, monitors can keep track of its trajectory.

The sheer volume of space also means that most space battles would be very short-lived. There won't be any dogfights. "Space is big, which means that a space-to-space engagement is not going to be both intense and long. It can only be one or the other:either a short, intense use of a lot of Delta V for big effect or long, deliberate use of Delta V for smaller or persistent effects."

Delta V is a change in velocity, and that requires fuel or propellant. But most satellites don't have the capability to change their velocity, and the few that might are severely fuel-limited.

"Operators of an attack satellite may spend weeks moving a satellite into an attack position during which conditions may have changed that alter the need for or the objective of the attack." And if the defending satellite is able to only slightly change its own path in response to an attack, then the attacking satellite may not have the capability or the fuel to change its own path to intercept it.

The authors also point out that timing is everything. Even if an attacking satellite can orient itself into the same orbital path as its target, there's still no guarantee of proximity.

"The nature of conflict often requires two competing weapons systems to get close to one another, " the report says. The authors use the example of an aircraft carrier needing to get close to its target, and another of jet fighters that also need to be close to each other. The same thing is true of satellites in space.

"Getting two satellites to the same altitude and the same plane is straightforward (though time and ?V consuming), but that does not mean they are yet in the same spot. The phasing—current location along the orbital trajectory—of the two satellites must also be the same. Since speed and altitude are connected, getting two satellites in the same spot is not intuitive." Instead, it takes perfect timing and meticulous preparation.

The authors also discuss another method of approaching a target called "plane matching, " A satellite maneuvers itself so that its orbital plane is aligned with a target. That has the advantage of allowing the attacker to dictate the time of the engagement. "By not initiating threatening maneuvers immediately, an attacker may try to seem harmless while waiting for an optimal time to attack, " the authors explain.

But none of these maneuvers happen quickly. "The physics of space dictate that kinetic space-to-space engagements be deliberate with satellites maneuvering for days, if not weeks or months, beforehand to get into position to have meaningful operational effects, " they write. But it can still be done.

And once the interception has been set up, "…many opportunities can arise to maneuver close enough to engage a target quickly."

There are natural limits to how maneuvering satellites in LEO can do. På den ene side, some phasing maneuvers can send the satellite into the Earth's atmosphere where it will be burned up. På den anden, it could be sent too far away from LEO, into the Van Allen Belts. So there are constraints on a satellite's maneuverability.

Satellites in geostationary orbits maintain the same relative position over Earth, so some of the mechanics of attacking and defending are different. Men samlet set, the same constraints are still in place. It takes time and energy to maneuver in space, regardless of the type of orbit.

But orbital and maneuverability considerations are only a part of what the report addresses.

The authors go on to discuss the types of attacks that can take place. Collisions, projectiles, and electronic jamming or disruption are covered in the paper. Each type has its own considerations and preparations.

But the authors also discuss the aftermath of some successful attacks:complications arising from debris. Additional debris could end up damaging other unintentional targets, like the attacker's own satellites or those of a neutral nation. There have been three successful anti-satellite attacks:one by China, one by the U.S., og Indien. The authors prepared a graphic to show the debris from each one.

The debris cloud from an attack is denser immediately after the attack and spreads out quickly. Even though debris density is lowered quickly, the debris spreads out over a larger area and is still hazardous.

The paper is a clear presentation of all of the difficulties with space battles and how much different they would be compared to air-to-air battles. But some other considerations that are still important are outside its scope.

What happens when one nation deduces that their satellites are about to be attacked? They won't sit on their thumbs. They'll likely denounce, threaten, and even retaliate here on Earth. A space attack could end up being a flashpoint for another terrestrial war.

There could end up being an arms race in space, where nations compete to outspend each other on space weaponry and other technology. That's a huge strain on resources for a world that should be focused on meeting the challenge of climate change.

Og, where does it all end? War in orbit? War on the moon? War on Mars? When will humanity figure it out and just stop?

En dag, maybe, there'll be a final war before we give it all up. But that won't likely be in the next 50 years.

And if there is a war in the next 50 years or so, it may involve satellites, and it may look a lot like how the authors of this report have laid it out:slow, calculated, and deliberate.