When did Piccard reach his record altitude of 23 km (75,500 ft)?

Question

Swiss physicist and balloonist Auguste Piccard reached world altitude records of 15.8 km (51,800 ft) in May 1931 and 16.2 km (53,000 ft) in August 1932, accompanied by Paul Kipfer in the former and by Max Cosyns in the latter flight.

The Wikipedia article writes he ultimately made 27 balloon flights and has gone as high as 23,000 meters (75,500 ft). When did Piccard fly to that altitude, and do you know a list of all his balloon flights?

Edit: Above assumptions and Wikipedia claim are outdated now that it's clear Piccard didn't make such flight and the WP article has been dealt with.

Answer 1

I strongly believe that the wikipedia author has misquoted a german language reference.

There are many places you can find reference to 25 (sometimes 27) altitude records being made (including Piccard in places), but the August 1932 flight to 53,000 ft seems to have been Piccard's last

The following year, Piccard broke his record with an ascent to nearly 55,000 feet (16,764 m), and within a few years, others had risen to nearly 61,000 feet (18,593 m). Since then, manned balloons have risen to over 113,000 feet (34,442 m)
_{Emphasis mine, source: https://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/auguste-piccard-and-paul-kipfer-are-first-enter-stratosphere}

A good breakdown of the 25 significant balloon altitude records can be found on wiki with the relevant section reproduced below.

• 1931-05-27: 15.781 km (51,770 ft) – Auguste Piccard and Paul Kipfer in a hydrogen balloon.
• 1932: 16.201 km (53,150 ft) -Auguste Piccard and Max Cosyns in a hydrogen balloon.
• 1933-09-30: 18.501 km (60,700 ft) USSR balloon USSR-1.
• 1933-11-20: 18.592 km (61,000 ft) Lt. Comdr. Thomas G. W. Settle (USN) and Maj Chester L. Fordney (USMC) in Century of Progress balloon
• 1934-01-30: 21.946 km (72,000 ft) USSR balloon Osoaviakhim-1. The three crew were killed when the balloon broke up during the descent.
• 1935-11-10: 22.066 km (72,400 ft) Captain O. A. Anderson and Captain A. W. Stevens (U.S. Army Air Corps) ascended in the Explorer II gondola from the Stratobowl, near Rapid City, South Dakota, for a flight that lasted 8 hours 13 minutes and covered 362 kilometres (225 mi).
• 1956-11-08: 23.165 km (76,000 ft) Malcolm D. Ross and M. L. Lewis (U.S. Navy) in Office of Naval Research Strato-Lab I, using a pressurized gondola and plastic balloon launching near Rapid City, South Dakota, and landing 282 km (175 mi) away near Kennedy, Nebraska.
• 1957-06-02: 29.4997 km (96,784 ft) Captain Joseph W. Kittinger (U.S. Air Force) ascended in the Project Manhigh 1 gondola to a record-breaking altitude.
• 1957-08-19: 31.212 km (102,400 ft) above sea level, Major David Simons (U.S. Air Force) ascended from the Portsmouth Mine near Crosby, Minnesota in the Manhigh 2 gondola for a 32-hour record-breaking flight. Simons landed at 5:32 p.m. on August 20 in northeastern South Dakota.
• 1960-08-16: 31.333 km (102,800 ft) Testing a high-altitude parachute system, Joseph Kittinger of the U.S. Air Force parachuted from the Excelsior III balloon over New Mexico at 102,800 ft (31,300 m). He set world records for: high-altitude jump; freefall diving by falling 16 mi (26 km) before opening his parachute; and fastest speed achieved by a human without motorized assistance, 614 mph (988 km/h).
• 1961-05-04: 34.668 km (113,740 ft); Commander Malcolm D. Ross and Lieutenant Commander Victor A. Prather, Jr., of the U.S. Navy ascended in the Strato-Lab V, in an unpressurized gondola. After descending, the gondola containing the two balloonists landed in the Gulf of Mexico. Prather slipped off the rescue helicopter's hook into the gulf and drowned.[a]

If Piccard would have broken his own record, I'm fairly certain it would have been documented in this list, but as you can see after the 1932 ascent the record was broken by others, with the US Navy breaking 23KM in 1956 - by which time Piccard had long-ago moved on to deep sea descent rather than stratosphere ascent

In the mid-1930s, Piccard's interests shifted when he realized that a modification of his high-altitude balloon cockpit would allow descent into the deep ocean.

Back to my original assertion, the final word will lie with whoever can check the reference from wikipedia:

Dr. Erich Tilgenkamp - Reisen in ungewöhnliche Räume - Eine autorisierte Biographie - Verlag neues Leben Berlin 1956.

Answer 2

Thanks to a link by @mins, The Guardian says (uncited):

The physicist made 25 further [totaling 27] balloon flights. In the mid-1930s, having climbed to an incredible 23,000m (14 miles) [...]

But, a NASA-published book says (also uncited):

Ultimately, Piccard made 27 balloon flights, setting a final record of 72,177 feet. They were altitudes that airplanes of the day could not touch.

72,177 feet is 21,999.6 m, which is 22 km and not 23, moreover the possible conversion from meter to feet in the NASA book makes it suspicious: the 22 km record by Anderson being misattributed to Auguste and converted to feet (more on that below), and the difference from The Guardian in the altitude makes both unreliable.

Jean – Auguste's twin brother – published a paper in 1938:

Auguste Piccard and his associates were able to make three flights with their original balloon (1931, 1932 and 1934). More flights were made with similar but larger stratosphere balloons from Russia and the United States. The most important of these flights was the National Geographic Society–U.S. Army flight of Stevens and Anderson (1935).

— Piccard, Jean. "Exploration by Balloon." The Scientific Monthly 47.3 (1938): 270-277. [emphasis mine]

Jean credits Auguste and associates with three flights, which agrees with Jamiec's answer. It takes one mistake in interpreting Jean's 1938 paper – see my bold emphasis – to propagate the incorrect claim of twenty-something flights by his brother Auguste.

This is also confirmed by comments from @mins (emphasis mine):

In this interview, in 1954 by the Swiss Radio, which is in French, Auguste Piccard talks about two ascents, and when asked if there were more, he mentions only from others, like "Americans":

• André Savoy:
  You made no more attempts to the stratosphere after 1932, but there was the attempt by your brother Jean [...], any other?
• Auguste Piccard:
  Yes Americans with Explorer climbed to 20,000 m, Russians who climbed a bit higher than me [...]

Answer 3

This is a just barely an answer, but: the most reputable source for any aviation related record is World Air Sports Federation / Fédération Aéronautique internationale - FAI

Auguste Piccard has two records of records in FAI database (pun intended), one of which is still current:

A-8th   Altitude    15 781 m    27 May 1931 Ratified - superseded since id 10634    
AA-14   Altitude    16 201 m    18 Aug 1932 Ratified - current record   id 6590

Now, if Piccard had flown higher in a verifiable undisputed manner, it should definitely show in FAI records. The fact that this is not the case does not exclude the possibility Piccard had in fact flown higher than 16201 meters, but there obviously is no significant proof to support this claim.

Piccard was an established and highly regarded scientist, and his flights were scientific experiments by nature. He did, as a scientist, with great certainty keep strict logs of his flights, and as I understand did not perform these experimental flights alone. So it is likely there was a witness on all flights. I'm not familiar with FAI requirements for setting world records. It may require more observers, perhaps.

I'm certain he did not "pull his stunts" for the sake of breaking records. While doing his experiments he got high (sorry, thats a lame pun but I'll let it fly), but the records were not the point. That may have been a reason not to seek ratification as world record for possible higher altitudes he may have ventured into.