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ctg kirjoitti:

http://www.spacedaily.com/reports/R...ombustion_chamber_pressure_says_Musk_999.html
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Rosmokosmos on antanut "vastineen"


Käänsin google kääntäjällä

Lyovochkin replied to Mask
Pyotr Lyovochkin, chief designer of NPO Energomash, developer and manufacturer of the famous RD-180 family of engines, commented on the PR statement of Ilona Mask about the “superiority” of the Raptor engine created by SpaceX:

“The SpaceX company creates the Raptor engine on oxygen and methane components or, as is customary in the Russian classification, the gas-gas scheme. In such schemes, such a pressure level in the combustion chamber is not something extraordinary - in our designs for these schemes we lay down the pressure level in the chamber over 300 atmospheres. And the parameter pressure in the chamber is not the output characteristic of the engine, such as thrust and specific impulse.

However, Mr. Musk, not being a technical specialist, does not take into account that the RD-180 engine for the Atlas launch vehicle uses a completely different fuel circuit - “oxygen-kerosene”, and these are other parameters of the engine operation. It is like comparing a diesel and a gasoline internal combustion engine. And if we take into account the fact that Energomash certified the engine with a 10% reserve, then the pressure in the RD-180 combustion chamber is above 280 atmospheres.

Despite the fact that our companies are competitors, we as engineers welcome the first successes of colleagues from SpaceX in the field of rocket engine building. Indeed, during the development of the Raptor engine, American engineers reached a record pressure level in the chamber. This indicates a fairly high level of development and production processes at SpaceX
https://www.roscosmos.ru/25999/

Niin ilmeisesti kammiopaineella ei ole tekemistä moottorin tehon kannassa vai mitä tässä yritetään sanoa?
Esim F1(Saturn) moottorissa paine 80bar mutta työntövoima 7000000N. Vs raptor 1500000(N)
 
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Passi kirjoitti:
Niin ilmeisesti kammiopaineella ei ole tekemistä moottorin tehon kannassa vai mitä tässä yritetään sanoa?
Esim F1(Saturn) moottorissa paine 80bar mutta työntövoima 7000000N. Vs raptor 1500000(N)
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Työntövoima on tärkeä ominaisuus, ilman sitä ei päästä yhtään mihinkään maan pinnalta. Olennaisempaa on kuitenkin moottorin ominaisimplussi ISP, eli paljonko polttoainetta kuluu sen työntövoiman saavuttamiseen.

Muskin mainitsema RD-180 on erinomainen ykkösvaiheen moottori, mutta myös huonomman moottorin puutteita voidaan ykkösvaiheessa korvata esimerkiksi kiinteää polttoainetta käyttävillä boostereilla. Tästä hyvä esimerkki on avaruussukkula, joka ei olisi päässyt omilla moottoreillaan yhtään mihinkään, joten kylkeen laitettiin heikolla hyötysuhteella, mutta valtavalla työntövoimalla toimivat boosterit. Silti valtaosa siitä energiasta, joka sukkulan kiertoradalle pääsyyn vaadittiin, tuli RS-25(SSME)-moottoreista, jotka olivat heikkoja työntövoimaltaan, mutta erittäin hyviä hyötysuhteeltaan.

Kammiopaine itsessään on sinänsä hyvä asia, mutta se riippuu suuresti valitusta polttoaineesta, moottorin suuttimesta jne. Jos nyt otetaan se Saturn V:n ykkösvaiheen kerosiinia käyttävä F-1 esimerkiksi, niin siinä on melko matala hyötysuhde, mutta toisaalta korkea työntövoima. Kakkos- ja kolmosvaiheissa käytettävä, vetyä polttava J-2 on taas hyötysuhteeltaan jo huomattavasti edellä Raptoria.

Kyseessä on monimutkainen yhtälö, ja jos halutaan käyttää samaa moottoria ja samaa vaihetta alusta loppuun, se vaatii kompromisseja.
 
A study published last year in the journal Science suggested liquid water is present beneath the south polar ice cap of Mars. Now, a new study in the AGU journal Geophysical Research Letters argues there needs to be an underground source of heat for liquid water to exist underneath the polar ice cap.

The new research does not take sides as to whether the liquid water exists. Instead, the authors suggest recent magmatic activity - the formation of a magma chamber within the past few hundred thousand years - must have occurred underneath the surface of Mars for there to be enough heat to produce liquid water underneath the kilometer-and-a-half thick ice cap. On the flip side, the study's authors argue that if there was not recent magmatic activity underneath the surface of Mars, then there is not likely liquid water underneath the ice cap.

"Different people may go different ways with this, and we're really interested to see how the community reacts to it," said Michael Sori, an associate staff scientist in the Lunar and Planetary Laboratory at the University of Arizona and a co-lead author of the new paper.
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http://www.marsdaily.com/reports/Ne...recent_underground_volcanism_on_Mars_999.html

Itse kannatan tätä tulivuori teoriaa.
 

NASA really wants to land astronauts on the moon in 2028. But to do that, the agency is looking to commercial space companies to build the landers, space tugs and refueling stations required to make a moon exploration effort that lasts.

"This time, when we go to the moon we're going to stay," NASA Administrator Jim Bridenstine told a roomful of space industry representatives here Thursday (Feb. 14). "So, we're not going back to the moon to leave flags and footprints and then not go back for another 50 years. We're going to go sustainably. To stay. With landers and robots and rovers — and humans."

The gathering at NASA's headquarters comes a week after the agency unveiled what it calls a Broad Agency Announcement calling on commercial space companies to submit ideas for lunar landers, tug-like transfer vehicles and refueling systems to gas up those vehicles for reuse. Interested companies have until March 25 to submit their ideas, with NASA aiming to make selections in May and issue contracts of up to $9 million for follow-up studies in July (just in time for the 50th anniversary of the Apollo 11 moon landing).

"This is going to be fast," said William Gerstenmaier, NASA's associate administrator of the Human Exploration and Operations. "We're going to need the best and brightest from you in industry. We're going to need the best and brightest from the international partner community to pull all this off."
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https://www.space.com/nasa-crewed-lunar-landers-moon-2028.html

The 21st century lunar architecture will use NASA's planned Gateway, an orbital space station near the moon, as a way station for astronauts en route to the moon. Transfer vehicles at the Gateway will ferry lunar landers to and from low lunar orbit. The landers (which consist of a descent element and reusable ascent element that carries the crew) would then make the final trip to the lunar surface.

Refueling spacecraft based at the Gateway will then resupply the transfer tugs and returning ascent vehicles for return trips to the moon. NASA leaders described it as an "open architecture" designed to foster new capabilities to explore the moon.

"We're doing it in a way that we've never done before," Bridenstine told reporters before the industry presentation.
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Leaderwolf kirjoitti:
Kuulaskeutuja? Falcon 9:lla? :unsure:
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Robotti

6eSSp9awZ4jPd4K3MG6CrU-650-80.jpg

https://www.space.com/43188-israel-first-moon-lander-spaceil-beresheet-photos.html
 
Avaruusvoimat.

President Donald Trump on Tuesday signed a directive centralizing all military space functions under a new Space Force, which will be overseen by the Department of the Air Force.

While it is technically up to Congress to approve the creation of the Space Force, a sixth military branch that would organize, train and equip a corps of military space personnel, Trump’s signing of Space Policy Directive 4 marks the first time the administration has made clear how the new service would fit into the existing military structure.
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https://www.defensenews.com/space/2019/02/19/trump-signs-off-on-organizing-the-space-force-under-the-air-forcefor-now/
 

Jotkut sanovat että Planeetta 9 tai Planeetta X ei ole siellä Kuiber Beltillä, vaan puuttuu kokonaan ja koko homma voidaan selittää niillä protoplaneetan kappaleilla mitä esim Ultima Thule edustaa ja miniplaneetoilla kuin Pluto tai MakeMake. Toiset väittävät että matematiikkaa käyttämällä ja laittamalla ison massan sinne kauas, niin koko aurinkokunnan malli lähtee pelittämään. Mikä on totuus, kukaan ei tiedä varmasti mutta toivottavasti lähitulevaisuudessa saamme vastauksen tähän ongelmaan.
 
Virgin Galacticin avaruusalus VSS Unity, toinen SpaceShipTwo-luokan alus, suoritti onnistuneen avaruuslennon 22.2.2019 yltäen 89,9 kilometrin korkeuteen. Aluksessa oli kolmen hengen miehistö.

 
Jukkis kirjoitti:
Sekään ei ole yleisesti kaikkien jenkkien määritelmä, vaan erityisesti USAFin oma virallinen raja.
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Kyllä vissiin nasa tuota käyttää.

Euroopassa käytetään karmanin rajaa (100km).

Kármánin raja on 100 kilometrin korkeudella merenpinnasta sijaitseva taso, jota varsinkin Euroopassa on totuttu pitämään rajana, joka erottaa maan ilmakehän ja avaruuden toisistaan.[1]
Raja on nimetty unkarilais-amerikkalaisen fyysikon Theodore von Kármánin mukaan. Hän laski, että tällä korkeudella maapallon ilman tiheys on niin pieni, ettei siipi toimi enää lentotekniikan käyttämän aerodynamiikan lakien mukaan.
 
The European Space Agency (ESA) is searching for potential spacesuit materials that would best protect future lunar astronauts from the inhospitable conditions of the moon.

On Jan. 19, the Paris-based intergovernmental organization signed a two-year agreement with Comex and its partners the German Institute of Textile Technology and Process Engineering and the Austrian Space Forum to investigate not only existing spacesuit materials but also more nascent innovations with useful properties such as self-healing capabilities, dust repellence and integrated circuitry.

"The identification and test of such materials could serve the development of future European spacesuits for spacewalks on the moon and is in line with ESA's exploration strategy to return to the moon in the coming decades," ESA officials said in a statement.

The project, dubbed Pextex, will commence with a workshop in May to discuss potential materials
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. https://www.space.com/european-space-agency-pextex-moonsuit-project.html

The ideal lunar spacesuit, ESA officials said, would be able to remediate any electrostatic buildup and provide electromagnetic protection for 8 or more hours. It must also be nontoxic and nonflammable, impermeable to water and fluids and able to bend 180 degrees.
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Kumipuku Kuukävelyyn? Nyt jos tiedätte sopivan materiaalin, niin muuta kuin tähän kilpailuun.
 
themis2.jpg


Late last week, the European rocket maker Ariane Group and the French space agency CNES announced the creation of an "acceleration platform" to speed development of future launch vehicles. The initiative, called ArianeWorks, would be a place where "teams work together in a highly flexible environment, open to new players and internationally."

"In this era of NewSpace and in the context of fierce competition, ArianeWorks will accelerate innovation at grassroots level, in favor of mid-tier firms and start-ups, with commitment to reducing costs a major priority," a news release sent to Ars states.

As part of the announcement, the organizations released a promotional video for the group's first step—a so-called Themis demonstrator. The goal of this project is to build a multiple-engine first-stage rocket that launches vertically and lands near the launch site. The rocket will be powered by Europe's Prometheus engine, a reusable liquid oxygen and methane engine that may cost as little as $1 million to build.

The new video is striking because of how similar the Themis demonstrator of "breakthrough technologies" looks to SpaceX's Falcon 9 rocket. Even the engines, with a thrust of 100 tons each, are similar to the output of the Merlin 1D that powers the Falcon 9 rocket. (One difference is that the Merlin 1D engine uses kerosene fuel instead of methane).

The promotional video shows a rocket taking off and then jumps to a landing, complete with four landing legs. A new rocket then takes off as another one lands—similar to concepts SpaceX has discussed for its next generation-rocket and Starship.
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https://arstechnica.com/science/201...able-rocket-that-looks-a-lot-like-a-falcon-9/
 
UWE-4_AutoB.jpeg


After 7 years of tireless development at the tu dresden, the spin-off, Morpheus Space has successfully ignited the world's smallest ion beam thruster on the "UWE-4" nano-satellite. Four of the thumb-sized thrusters are located on UWE-4, the 1 kg nano-satellite of the University of Wurzburg.

This enabled the Germany-based company to operate the first electric thruster in this satellite size in space. The primary objective of the satellite mission is to test the propulsion system in orbit in order to obtain space qualification, the final and most important milestone.

The innovative satellite propulsion system called "nanofeep" provides mobility to the most commonly used nano-satellites in the commercial space industry. Mobility is the most crucial capability for satellites that is necessary to secure a sustainable space environment for humankind.

So far, the control of the large networks of shoebox-sized satellites is non-existent or very limited at best. This means that the prevention of collisions with each other or with existing space debris becomes in the majority of cases impossible.

In addition, space debris will continue to grow exponentially through the thousands of newly planned satellites over the next few years. This could potentially reach a point where low earth orbits will become unusable and space based services become unavailable for decades or even centuries.

Morpheus space offers satellite operators and manufacturers the opportunity to protect themselves against collisions and to return the decommissioned satellites into earth's atmosphere.

"I am incredibly proud of our entire team, who have worked extremely hard for this great success", says Ddaniel Bock, CEO of Morpheus Space.

"With the successful demonstration of our thrusters, we are approaching our biggest goal: Giving the nano-satellites the much-needed mobility and thus keeping the orbit of our beautiful planet clean and access to space a continued privilege of humankind."
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http://www.spacedaily.com/reports/S...satellite_propulsion_system_in_orbit_999.html

https://directory.eoportal.org/web/eoportal/satellite-missions/u/uwe-4
 
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