How fast can we travel in space? Speed records and real limits

The fastest any human-made object has ever travelled is about 192 km/s (692,000 km/h, or 430,000 mph), a speed NASA’s Parker Solar Probe reached on 24 December 2024 as it swung closest to the Sun. That is fast enough to cross the continental United States in well under a minute, yet it is still only about 0.064% of the speed of light.

Parker’s record is a peak speed gained by falling toward the Sun, and the probe stays in solar orbit. The fastest spacecraft actually leaving the solar system is Voyager 1, cruising at about 17 km/s (roughly 61,000 km/h). The fastest humans are still the Apollo 10 crew, who hit 39,897 km/h (about 11.1 km/s) on their return from the Moon in May 1969.

Key facts about spacecraft speed

• Fastest human-made object: Parker Solar Probe, 192.22 km/s relative to the Sun, measured at its closest approach on 24 December 2024
• Fastest object leaving the solar system: Voyager 1, about 17.0 km/s relative to the Sun, about 25.9 billion km from Earth by November 2026
• Fastest launch: New Horizons left Earth at about 58,536 km/h (16.26 km/s) in January 2006
• Fastest humans: Apollo 10, 39,897 km/h (24,791 mph) relative to Earth at atmospheric entry on 26 May 1969; Artemis II did not break this record in 2026
• Nearest star at Voyager 1’s speed: about 75,000 years (calculated below)

What is the fastest spacecraft ever?

The answer depends on what “fastest” means and what the speed is measured against. A spacecraft’s speed relative to the Sun can differ from its speed relative to Earth by tens of kilometres per second, so the table below states the reference frame for every record.

Sources: NASA, Guinness World Records and JHU APL for Parker; NASA Science for Voyager 1, New Horizons and the ISS; NASA History for Apollo 10; post-flight reporting by IFLScience and Ars Technica for Artemis II, whose two published entry speeds differ slightly. Km/s values for Voyager 1 and Apollo 10 are SciQuest conversions.

For scale, the ISS figure is the speed needed to stay in low Earth orbit. Our guide to how big the International Space Station is explains what that orbit looks like.

Why did Parker Solar Probe go so fast?

Parker did not get its record from a giant engine. It fell toward the Sun. A spacecraft on an elongated orbit speeds up as it drops closer to the Sun and slows down as it climbs away, just as a ball speeds up rolling downhill.

Mission planners used repeated Venus flybys to shrink Parker’s orbit, so each close pass went deeper into the Sun’s gravity. Guinness World Records notes that the 6 November 2024 Venus flyby set up the record pass, which took the probe within about 6.2 million km of the Sun’s surface.

That is why Parker’s speed is not a useful “cruise speed” for interstellar travel. The probe stays bound to the Sun and slows down on every outbound leg. It cannot keep that speed and head for another star.

How fast have humans travelled?

NASA credits Apollo 10’s Thomas Stafford, John Young and Eugene Cernan as the fastest humans. Their capsule was moving at 24,791 mph (39,897 km/h) when it met Earth’s upper atmosphere on 26 May 1969, after a trip around the Moon.

Artemis II, which splashed down on 10 April 2026, was expected by some to break that mark. It did not. According to IFLScience, NASA chose a gentler “lofted” entry after heat-shield problems on Artemis I, and post-flight reports put the capsule at roughly 39,500 km/h, just below Apollo 10. Artemis II did set a different record: its crew went 252,756 miles (about 406,770 km) from Earth, farther than any humans before, beating Apollo 13’s 1970 record.

How long would it take to reach Mars, Pluto or the nearest star?

Real trips are not straight lines at a constant speed. Spacecraft follow curved paths around the Sun, coast most of the way and use planetary flybys to save fuel. These are measured journey times from actual missions:

Sources: NASA, JPL and NASA Science mission pages listed below. NASA says direct trips to Mars generally take seven to ten months, depending on where the planets are. For distances, see how far Mars is from Earth.

Worked calculation: reaching Proxima Centauri

Proxima Centauri, the nearest star to the Sun, is about 4.24 light-years away. One light-year is the distance light travels in a year, about 9.461 × 10¹² km.

• Distance: 4.24 × 9.461 × 10¹² km ≈ 4.01 × 10¹³ km
• At Voyager 1’s 17.0 km/s: 4.01 × 10¹³ km ÷ 17.0 km/s ≈ 2.36 × 10¹² s. Dividing by 3.156 × 10⁷ seconds per year gives about 74,800 years.
• At Parker’s peak 192.22 km/s: about 2.09 × 10¹¹ s, or roughly 6,600 years. This is a hypothetical: Parker cannot hold that speed or leave the solar system.
• At 20% of light speed: 4.24 ÷ 0.2 = 21.2 years, the kind of speed proposed for laser-driven lightsails (see below).

NASA’s own estimate, using a slightly higher Voyager speed of 17.3 km/s, is “over 73,000 years.” Voyager 1 is not actually heading toward Proxima Centauri. NASA expects it to be about 25.9 billion km from Earth in November 2026, which is roughly one light-day. For more on that scale, see how long it takes to travel one light-year.

Why can’t rockets simply go faster?

A rocket gains speed by throwing propellant backward. The faster it throws that propellant, the more speed it can gain from each kilogram. Engineers measure this with specific impulse, which NASA defines as thrust divided by the weight flow of propellant. It is measured in seconds and is proportional to effective exhaust velocity.

Specific impulse is not the same as thrust. Chemical rockets produce enormous thrust but have limited exhaust speeds, so reaching very high speeds needs huge amounts of propellant. Electric thrusters have much higher specific impulse but push very gently.

That is why mission designers rely on gravity assists. A close pass by a planet can change a spacecraft’s speed relative to the Sun without burning fuel. New Horizons’ February 2007 Jupiter flyby added about 14,000 km/h and, according to NASA, cut three years from its trip to Pluto.

Which propulsion technologies could make spacecraft faster?

Ion engines. Ion engines are efficient but very gentle. JPL said NASA’s Dawn needed four days at full throttle to go from 0 to 97 km/h. Patience pays, though: by June 2010 Dawn had changed its speed by more than 4.3 km/s, then a record for propulsive speed change, using less than 165 kg of xenon.

Solar sails. These use the tiny push of sunlight. IKAROS unfurled a square sail about 14 m on each side (about 20 m corner to corner), and JAXA reported controlling its orientation using liquid-crystal panels built into the sail.

Nuclear thermal rockets. These would heat hydrogen in a reactor and could have much higher specific impulse than chemical engines. NASA notes the United States ground-tested about 20 reactors and engines under the Rover/NERVA programmes between 1959 and 1972, but none flew, and the programme was cancelled in 1973. The DRACO in-space demonstration announced by NASA and DARPA in 2023 was ended in 2025, after NASA’s fiscal 2026 budget request removed its funding. DARPA said that cheaper launches had weakened the return on investment.

Breakthrough Starshot. This is a proposal to use a ground-based laser to push gram-scale lightsail probes to “a significant fraction of light speed,” reaching Alpha Centauri “in just over 20 years from launch.” The initiative states that a number of hard engineering challenges remain to be solved. Nothing has flown.

Warp drives. Miguel Alcubierre’s 1994 paper showed that general relativity allows a spacetime geometry that contracts space ahead of a ship and expands it behind. The paper itself says exotic matter would be needed. No known material provides it, and the idea is not a form of instant travel. The related idea of shortcuts through spacetime is covered in our explainer on whether humans could create a wormhole.

What is the most powerful rocket today?

Saturn V, which launched Apollo crews, is no longer the most powerful rocket ever flown. NASA puts its liftoff thrust at about 7.5 to 7.6 million pounds-force (roughly 34 MN). NASA’s Space Launch System, first flown on 16 November 2022, produces up to 8.8 million pounds-force (about 39 MN), which NASA says is 15% more than Saturn V.

SpaceX’s Starship is more powerful still. Its Super Heavy booster uses 33 Raptor engines, and Spaceflight Now described its July 2026 test flight as climbing on about 16 million pounds of thrust (roughly 71 MN), about twice Saturn V’s. The stacked vehicle stands about 124 m (407 ft) tall and was still in flight testing as of 2026.

Liftoff thrust measures how much a rocket can lift out of Earth’s gravity. It does not set a spacecraft’s top speed. That depends on the whole trajectory, including upper stages, gravity assists and where the spacecraft is going.

What limits space travel speed?

Light travels at exactly 299,792.458 km/s, and in relativity nothing with mass can reach that speed. Long before that ceiling matters, propellant does: every extra kilometre per second needs more propellant, which must itself be carried. The concepts that might break today’s limits, from laser sails to nuclear engines, still face unsolved engineering, regulatory or physical obstacles.

So the current answer is this: uncrewed spacecraft leave the solar system at about 17 km/s, one probe briefly reaches about 192 km/s near the Sun, and humans have not exceeded about 11 km/s.

Related reading

• How long does it take to travel one light-year?
• How far away is Mars from Earth?
• Can humans create a wormhole? What physics allows

Update note: This article was substantially revised on October 12, 2026, to put the answer first; correct the Parker Solar Probe record (192.22 km/s, 24 December 2024) and the Proxima Centauri travel-time arithmetic; add Voyager 1, New Horizons, Apollo 10 and Artemis II with reference frames; correct the IKAROS sail size and the explanation of specific impulse; update the status of DRACO (cancelled in 2025); replace the outdated claim that Saturn V is the most powerful rocket; describe the Alcubierre warp drive accurately; and add sources. It was drafted with AI assistance and checked against the sources listed below.

Sources

• NASA Scientific Visualization Studio, Parker Solar Probe – Extended Mission
• NASA Science, Parker Solar Probe
• Guinness World Records, Fastest spacecraft speed
• NASA Science, Voyager 1 and Voyager: Where Are They Now?
• NASA Science, New Horizons; Johns Hopkins APL, NASA’s Pluto Mission Launched Toward New Horizons (2006)
• NASA History, 50 Years Ago: Apollo 10 Clears the Way for the First Moon Landing
• NASA, NASA Welcomes Record-Setting Artemis II Moonfarers Back to Earth
• IFLScience, Artemis II Was Expected to Break Several Records, but Afterwards One Was Notably Absent (June 2026); Ars Technica reprint, The fastest humans in the galaxy just got a spiffy patch to prove it (June 2026)
• NASA, Space Station Facts and Figures
• NASA, How Long Does It Take to Get to the Moon, Mars, Jupiter? We Asked a NASA Expert
• NASA JPL, Touchdown! NASA’s Mars Perseverance Rover Safely Lands on Red Planet
• NASA Imagine the Universe, The Nearest Neighbor Star; NASA APOD, Proxima Centauri: The Closest Star
• NIST, Speed of light in vacuum
• NASA Glenn Research Center, Specific Impulse
• NASA JPL, NASA’s Dawn Spacecraft Fires Past Record for Speed Change
• JAXA, Small Solar Power Sail Demonstrator IKAROS
• NASA Technical Reports Server, Nuclear Thermal Propulsion Ground Test History; NASA, Nuclear Thermal Propulsion: Game Changing Technology for Deep Space Exploration
• Breaking Defense, DARPA’s DRACO nuclear propulsion project roars no more (June 2025)
• Breakthrough Initiatives, Breakthrough Starshot
• Alcubierre, M., The warp drive: hyper-fast travel within general relativity, Classical and Quantum Gravity 11, L73 (1994)
• NASA, What Was the Saturn V?; NASA, Space Launch System
• Spaceflight Now, Starship test flight coverage (July 2026)