Landing on Venus

A lander reaches Venus at about 11 km/s, and the atmosphere does nearly all the braking. NPO Lavochkin's account of Venera 7 in 1970 gives the numbers: drag cut the capsule's speed from 11.5 km/s to 200 m/s with loads peaking at 350 g, and the parachute opened at about 55 km, where the outside pressure was near 0.7 atmospheres. NSSDCA gives the planned release pressure as 700 mb and says that level is now known to lie at about 52.5 km. The air lower down is so thick that later landers used parachutes only in the upper layers. NSSDCA's record of Vega 2 has the parachute released at 47 km, after which the lander fell under a disc-shaped aerobrake and touched down at 03:00:50 UT on 15 June 1985, some 51 minutes later. Conditions at the bottom vary little: Lavochkin gives 465 °C and 94.7 atmospheres for Venera 14, and 460 °C and 90 atmospheres at the Venera 9 and 10 sites.

Venera 7 ran into both halves of the problem, survival and communication, on the same day. Its parachute ripped about six minutes after opening fully, NSSDCA says, and the capsule struck the ground at roughly 16.5 m/s at 05:34:10 UT on 15 December 1970. The signal seemed to stop; only later analysis of the recordings found a weak signal that went on for 23 minutes. Lavochkin adds that the received signal fell almost thirtyfold at touchdown, which could mean wind acting on the capsule or the capsule tipping over, and NSSDCA suspects it bounced and came to rest on its side. Lavochkin calls it the first craft in the world to reach the surface of Venus, and NSSDCA the first to return data from the surface of another planet.

From Venera 9 and 10 in 1975 the landers took the shape they kept until 1985: an insulated pressure sphere, rated by Lavochkin for an outside pressure of 10 MPa, with an aerodynamic braking disc on top and a toroidal landing ring underneath. The Soviet yearbook for 1976, reproduced on the Epizody kosmonavtiki archive site, says the disc alone slowed the craft to about 7 m/s once the main parachute had been dropped below the clouds. A passage credited to Mikhail Marov on the same site has Venera 9 touching down at 7 to 8 m/s on a slope of 15 to 20 degrees and resting tilted by 10 to 15 degrees. Venera 8, still on a parachute in 1972, met the ground at 8.3 m/s, according to Lavochkin.

Radio geometry decided where a lander could come down long before geology had a say. Venera 4 to 7 all arrived on the night side, and Venera 7 landed 2,000 km from the morning terminator. Venera 8 was sent to the sunlit side, landing 500 km past the terminator, and Lavochkin explains the cost: in daylight Earth would stand 30 to 50 degrees from the local vertical, so a second antenna was thrown out after landing. From 1975 each lander talked to its own carrier instead, the orbiters of Venera 9 and 10 and the flyby buses of Venera 11 and 12, Venera 13 and 14 and Vega 1 and 2. That opened up the side of Venus lit by the Sun but invisible from Earth, in Lavochkin's words, and tied each lander's life to the relay. Venera 10 transmitted for 65 minutes, until its orbiter went out of range (NSSDCA), and Venera 13's panoramas ran for 127 minutes before reception was stopped by command from Earth. A weak burn sent Venera 14's bus past at 26,050 km (Lavochkin; Siddiqi says 36,000), 10,000 km closer than full reception needed, and data stopped in the 57th minute.

Inside those limits the scientists still had aims. Lavochkin says the Venera 13 and 14 sites were chosen to characterise the relief and rocks of the planet's most typical geological provinces, one on hilly upland and one on smooth lowland. The 1986 Soviet overview of the Vega results (NASA TM-88516) explains that Vega 2 went to the north-east of Aphrodite Terra because the high mountain regions had never been sampled, and that both Vega landers had to use the night side because of the flight geometry toward Halley's comet. An aim was a box on the map. Lavochkin lists Venera 14's nominal point as 16 S, plus or minus one degree, and 314 degrees, plus or minus one degree; the lander came down at 13 deg 15 min S, 310 deg 09 min, about 490 km away. Even a modern design has a long throw: at the 2019 Venera-D workshop, the planned lander's range from atmospheric entry to touchdown was given as 200 km.

No one watched the landers arrive from above, so every position is a calculation from tracking data: the incoming trajectory, the timing of each event and the Doppler shift of the radio signal, which, Lavochkin writes of Venera 7, let the team work out the distance travelled, tie each temperature to a height and fix the moment of touchdown. A computed position is only as good as its map. Before Magellan, the pole of Venus and its rotation rate came from Earth-based radar; Magellan's images gave M. E. Davies and colleagues a period of 243.0185 days and a new pole in 1992. Today's convention, in the IAU gazetteer, counts latitude planetocentrically and longitude east from 0 to 360 degrees, with zero longitude set by the central peak of the crater Ariadne. A point quoted in 1975 and a point read off a Magellan mosaic can differ for that reason alone, and most sources here never name their frame.

The positions used in modern studies come from one Russian paper that is hard to find. E. L. Akim and V. A. Stepanyants re-stated the landing points on the new Magellan map in Astronomicheskii Vestnik, the journal published in English as Solar System Research; both also appear as co-authors of the 1992 Davies paper. The citation year is unsettled: Basilevsky, Nikolaeva and Weitz dated the paper 1992 in October of that year, while Weitz and Basilevsky in 1993 and A. M. Abdrakhimov in 2001 dated it 1993. No online copy was found; the numbers survive in papers that quote them. Abdrakhimov repeated the same sentence for each site: 'Radius of ellipse of probable error in the lander position is 150 km.' The seven centres are Venera 8 at 10.70 S, 335.25 E; Venera 9 at 31.01 N, 291.64 E; Venera 10 at 15.42 N, 291.51 E; Venera 13 at 7.55 S, 303.69 E; Venera 14 at 13.05 S, 310.19 E; Vega 1 at 8.10 N, 175.85 E; and Vega 2 at 7.14 S, 177.67 E. These are the seven landers that analysed surface rock; Venera 7, 11 and 12, which did not, are still printed in whole degrees: 5 S, 351 E; 14 S, 299 E; and 7 S, 294 E.

A circle 150 km in radius covers about 70,700 square kilometres. Other authors describe the same uncertainty differently. The report of the 2019 Venera-D workshop at IKI speaks of 'the large (300-km-diameter) landing ellipse', which matches Abdrakhimov. The 2007 abstract by Aittola, Raitala, Basilevsky, Ivanov and Head gives the Venera and Vega error circles as D = 200 km, a third narrower. Neither source explains the difference. The circle is also what the geology rests on. Abdrakhimov's maps can say only that wrinkle-ridged plains fill about 60 percent of the Venera 9 circle, ridged and fractured plains about 21 percent and tessera about 14 percent, which makes the plains the likeliest ground under the lander and nothing more certain.

Published positions fall into families, and many disagreements come from mixing them. Soviet texts of the time carry their own figures: Lavochkin places Venera 13 at 7 deg 30 min S, 303 deg 11 min, about 53 km from the Magellan-frame centre, and Venera 14 at 13 deg 15 min S, 310 deg 09 min, about 22 km from it. NASA's NSSDCA catalogue prints values without saying where they came from, such as 16 N, 291 E for Venera 10, about 80 km off. Secondary books add slips of their own. Asif Siddiqi's NASA history Beyond Earth prints Venera 9 at 290.64 E, an apparent one-digit slip worth about 91 km, and describes Venera 8 as landing within 'a 10-mile radius' of 10.7 S, 335.25 E where the ballistics solution gives 150 km. Quoted distances between twins disagree too: the 1976 Soviet yearbook, Lavochkin and Siddiqi all put Venera 10 about 2,200 km from Venera 9, while every pair of coordinates quoted on this page, Siddiqi's included, gives about 1,650 km.

Vega 2 shows how far apart the families can drift. Five positions are in print: 7.14 S, 177.67 E in the Magellan frame; 7.5 S, 179.8 E in the 1986 Soviet overview; 6 deg 27 min S, 181 deg 5 min in the Soviet yearbook for 1986; 7.2 S, 179.4 E in Siddiqi; and 8.5 S, 164.5 E in NSSDCA. The first four lie within about 365 km of one another. NSSDCA's value sits about 1,390 km west of the Magellan-frame point and about 1,750 km from the yearbook's, and no Soviet or Russian source for it was found. The balloon that rode down in the same entry vehicle offers a check. Its first position in the Planetary Data System table, at 02:18:22 UT on 15 June 1985, is 6.18 S, 177.95 E, about 106 km from the Magellan-frame landing point: inside the 150 km circle, though just outside a 100 km radius if the 200 km reading is used. The table does not name its coordinate frame. The 1986 overview gives the same pair of numbers for the Vega 2 landing site and for the start of the balloon's drift, which suggests that its landing site marks the arrival area of the entry vehicle.

Landing times hide a second trap: different clocks. Soviet announcements gave Moscow time of reception on Earth, and Siddiqi notes for Venera 9 and 10 that only reception times were announced. NSSDCA often lists spacecraft event time, and for Venera 7 says it subtracted a light time of 3 minutes 22 seconds. For Vega 2 the conventions fit: the 1986 overview's touchdown at 6 h 6 min 46 s Moscow time, read as UT plus three hours, falls 5 min 56 s after NSSDCA's 03:00:50 UT, and JPL's Horizons ephemeris gives a light time of 5 min 59 s that morning. The 1976 Soviet yearbook, which names no time scale, has Venera 10 enter at 7 h 00 min and land at 8 h 13 min 06 s, or 04:00 and 05:13:06 UT if read as Moscow time. NSSDCA and a Russian text credited to Marov give 01:02 and 02:17 UT, close to three hours earlier, which looks like one time-zone conversion too many; Siddiqi pairs the 01:02 entry with a 05:17:06 landing. Venera 7 shows the reverse: Lavochkin's 8 h 34 min 10 s, again with no time scale, sits exactly three hours after NSSDCA's 05:34:10 UT, yet NSSDCA calls its figure spacecraft time, 3 min 22 s before reception. If Lavochkin's is Moscow time of reception, both cannot be right.

On azmth each landing pin keeps every published solution beside its source, and none is averaged or quietly dropped. Where the Magellan-frame solution exists it leads, drawn with its 150 km circle and a note on the 200 km reading. For Venera 7, 11 and 12 the whole-degree figures stand with no stated error; rounding alone can hide up to about 53 km in each coordinate. The capsules of Venera 4 and Venera 5 and 6 carry estimates only, and the four Pioneer Venus probes take their impact points from NASA's Planetary Data System. Each time on a pin says which clock it uses. The 2020 Venera-D workshop report still describes the Venera and Vega sites by their 300-km ellipse and points to the Mars remedy: descent imagers combined with panoramas after landing, 'to pinpoint the precise landing site'.

The circles were drawn on Magellan images so that geologists could ask what the landers had analysed. Catherine Weitz and Alexander Basilevsky mapped all seven in 1993 and found plains dominant at every one. At the five sites where the landers measured a tholeiitic basalt chemistry, they found lava flows whose shapes suggest low viscosity; at Venera 8 and 13, where the chemistry was non-tholeiitic, they found unusual volcanic features, and they judged a steep-sided dome, lamprophyre-like lavas or ash beds the likeliest material under Venera 8. Basilevsky's 1997 return to the Venera 8 site added an unusually dense field of small volcanic shields as a possible source, a conclusion he called very tentative. Abdrakhimov, who with Basilevsky later reviewed the geology of all seven regions in Solar System Research (2002), turned the maps into percentages circle by circle: shield plains about 75 percent of the Venera 8 circle, lobate plains about 53 percent of Venera 14's, wrinkle-ridged plains about 98 percent of Vega 1's and more than 99 percent of Vega 2's. Any sentence of the form 'Venera 14 sampled lobate plains' is shorthand for 'lobate plains cover most of a disc 300 km wide'.

A later argument asks whether the landers touched those units at all. In 1992 D. B. Campbell and colleagues catalogued 57 parabola-shaped features around young craters in Magellan data, several hundred to about 2,000 km across, and explained them as fine debris thrown into the upper atmosphere at impact and carried west by the zonal winds. Basilevsky, James Head and Abdrakhimov then drew model parabolas around every crater wider than 11 km near the Venera and Vega sites and found that they cover 80 to 90 percent of those regions. Their 2004 paper proposed that the layered, weak rocks in the Venera panoramas might be partly lithified parabola deposits, in which case the chemistry could describe material dug from depth somewhere else. Aittola and colleagues carried the idea into site selection in 2007, testing candidates against model parabolas, such as tessera near the crater Quimby at 5.7 S, 76.7 E and shield plains in western Sedna Planitia at 43.5 N, 333.5 E.

In May 2026 Basilevsky and Head restated the case in Solar System Research. The surface material at all seven sites, they wrote, 'may represent ejecta from impact craters located elsewhere, deposited from the atmosphere at the landing sites in the form of radar-dark parabolas', and future landers should drill several metres and avoid mapped parabolas. Russia's science ministry publicised the paper, and on 21 August 2026 Moskovsky Komsomolets ran an interview in which Basilevsky said that no Soviet lander had come down between parabolas and that about 20 to 30 percent of the surface would remain open once the parabolas were mapped. Three details in the newspaper need care. Basilevsky dates the discovery to the early 2000s, which fits the 2004 link to the landing sites; the parabolas themselves were described in 1992. It reports, citing him, that the landers drilled a few decimetres, while Siddiqi describes Venera 14's soil sample as taken from 30 mm down. The newspaper also prints Basilevsky saying the ejecta is blown from west to east, while Campbell's paper has the particles carried west by the zonal winds and the 2007 abstract places the source craters east of the sites they cover.

Behind the ballistics stood people who planned the arrivals. Mikhail Marov, who died on 30 November 2023, is described in the Russian Academy of Sciences obituary as one of the scientific leaders of the planetary missions who took part in working out the strategy and flight schemes of the landers; he held a Lenin Prize. Russian texts credited to him give positions and local times for the landings, among them Venera 9 at 31.01 N, 291.63 E with the Sun 33 degrees from the zenith at 13:12 local solar time. His longitude differs from the Magellan-frame value by a hundredth of a degree, less than a kilometre.

Nothing has landed since. IKI's page for Venera-D still cites the 'ten successful landings', with up to two hours of work on the surface, and notes that no lander or balloon has made direct measurements for the last 40 years; its instrument list includes a landing camera. A catalogue published online on 28 April 2026 by Luca Forassiepi and colleagues counts remains from 15 missions 'concentrated between 1965 and 1985' and argues that titanium, ceramic and aluminium parts are likely to survive, albeit oxidised, corroded and possibly deformed (see what we left at Venus). Where those parts lie is still a circle 300 km wide, and the case for the descent cameras planned for Venera-D and DAVINCI, neither of which had flown as of 26 September 2026, is written in those circles.